Well explained captainF.... Seeing how were now up to sen 620 or so, that basically means any newhires can plan to be FOs for upwards of two decades unless we keep most of not all out 767s.
In this industry timing is everything and the guys who got hired in 2009,2010 timed it well, the 2011 and 2012 guys less so, especially 2012... Minimum 10 years to the bottom of the 717 list.
There are literally dozens of under 40 year old captains now, and retirement are about half or less that of the other Legacies.
Truth be told, your last statement may be valid for the younger senior guys on our list, but if you're an older guy hired after 2011, a combined seniority list with American or Delta will mean a much faster upgrade due to massive retirements at those carriers.