That's just simply not true:

Delta currently contracts for operation of 343 50-seat aircraft and is contractually obligated to its DCI partners to operate 311 50-seat aircraft through the end of 2015.* Importantly, Delta has obligations for many of these 50-seat aircraft until 2024.* But as a result of looming maintenance costs, high fuel prices and customer preferences, the Company is seeking to substantially reduce the number of 50-seat aircraft operated by its DCI carriers, as quickly as possible.* The rumor that, absent this deal, Delta will simply send the 50-seaters to the desert on their own is at best partially true; over time, it will probably happen, but not for well over a decade.*

The tentative agreement allows Delta earlier access to an additional 70 76-seat aircraft, but only if they first add to the mainline fleet 88 SNB aircraft (recently identified by the Company as B-717s).* The TA requires that the addition of these 76-seat aircraft will, in turn, trigger a further reduction in the number of 50-seat aircraft that DCI may operate.* The Company plans to accomplish this reduction by exchanging with the DCI carriers 76-seat aircraft for 50-seat aircraft on approximately a 2 for 1 basis (i.e. two 50-seat RJs removed from operation for each 76-seat RJ placed into operation).* At the end state, the number of 50-seat aircraft must be reduced to 125 from the 311 (almost a 60 percent reduction) that the Company would otherwise be contractually obligated to without this agreement.

Current PWA Limits
No limit on propeller-driven aircraft up to 70 seats and 70,000 lbs.
No limit on jet aircraft up to 50-seats and 65,000 lbs.
Currently at 343 50-seat jet aircraft
No more than 255 70 and 76-seat jet aircraft that may weigh up to 86,000 lbs.
Currently at 102 70-seat jet aircraft and 153 76-seat jet aircraft (total of 255)
Weight exception for 36 Compass EMB-175 at 89,000 lbs.
Baseline of 153 76-seat jet aircraft that may weigh up to 86,000 lbs.
3 for 1 growth of 76 seat aircraft once there are more than 767 aircraft on the mainline.* Up to a maximum of 255 76-seat aircraft
TA Limits
End state cap of 450 DCI aircraft
Exception for propeller-driven or turboprop aircraft of up to 37 seats and/or 37,000 lbs.
Exception for Delta Private Jets of up to 19 seats and 65,000 lbs.
Five aircraft may weigh up to 99,900 lbs.
Exception for up to nine aircraft operated under a prorate agreement with Chautauqua Airlines or Shuttle America, seating capacity up to 44 seats and less than 65,000 lbs.
End state cap of 125 50-seat aircraft of up to 65,000 lbs. based on ratio reduction
Company plans to have 343 50-seat jet aircraft on July 1, 2012
Under TA, reduction of 50-seat aircraft based on deliveries of new 76-seat aircraft
Zero future growth allowed
Immediate hard cap of 102 70-seat aircraft of up to 86,000 lbs.
Zero future growth allowed
End state hard cap of 223 76-seat aircraft of up to 86,000 lbs.
Existing weight exception for 36 Compass EMB-175 at 89,000 lbs. remains
Requires 1.25 SNB in fleet for each 76-seat aircraft added above current 153 in fleet up to maximum of 223
This is a reduction of 32 76-seat aircraft from current PWA limit (based on the current 3:1 growth metric and up to 255 76-seat aircraft)
The combined cap on 70 and 76-seat aircraft increases to 325 (102 70-seat + 223 76-seat)
Eliminates 3:1 growth over 767 mainline aircraft up to 255
Zero future growth allowed
*
Delivery of additional 76-seat aircraft is prohibited until SNB aircraft are first added to the mainline fleet, and then, a simultaneous reduction of 50-seat aircraft is required.* This is an event-based process and not time or date-based.* As Delta implements their business plan and adds more SNBs, only then may they add more 76-seat aircraft, while also removing 50-seat aircraft.* Once a 50-seat aircraft is removed, the number of allowable 50-seat aircraft is capped at that level until the next removal and so on.* That cap can then never increase.
*
When the up-gauging is complete, the mainline share of domestic flying will have increased from the present 54% to 64% (based on Delta’s current business plan).* Put another way, this will result in a significant increase in mainline pilots’ share of Delta domestic flying.*
*
As SNBs are added to the fleet, allowing faster access to the first additional 76-seat aircraft, a required minimum ratio of domestic mainline block hours to DCI block hours will be established and must be maintained.* (For this purpose, domestic mainline block hours includes flying on all narrow body aircraft and all B-767-300 (non – ER) aircraft.)* Under the minimum block hour ratio in this TA, Delta pilots will fly no less than 61% of the total Delta domestic system block hours once the last group of 76-seat aircraft are added.* In other words, any reduction of domestic mainline block hours below a 1.56 ratio will trigger a mandatory reduction in DCI block hours in order to maintain the 1.56 ratio. *Any future growth of Delta aircraft, will, by definition, be mainline growth.* Even if Delta does not fully execute its business plan, we will have in place guarantees for our share of the domestic system flying, guarantees that do not exist under the current contract.* We will be the only legacy airline pilot group that has gained domestic flying without flying small aircraft and/or agree to substantially lower pay rates or different work rules.

Mainline has to grow in order for those 76s to show up. Furthermore, to think that the high operating costs of those 50s will not affect you and pawning it off as "it's not my problem" is just outright irresponsible. Either we allow the restructuring of those agreements or the money that has to be spent on operating those 50s will not go into our pockets but on them therefore perpetuating more money being put into DCI and not into DAL pilots. With the 717 purchase alone the company can increase the 76s up to 255. This TA allows only 223 76s (which is a reduction in the amount of 76s allowed on the property). The relief is on allowing 102 additional 70s (to offset the high cost of the 50s). It's an upgauge in equipment on most routes (with a first/business class) which makes our customers happy because the majority of them will no longer have to ride on those god forsaken 50s again.

How is it acceptable that another carrier performs more than half of DAL's domestic flying? This TA puts more of that flying back at mainline.

That's just what I am seeing.

Another great post. Has ACL read this yet?