look - it's all about frequency. RJ's are sanwiched in between mainline to keep up the frequency or:
provide thin markets at an elevated price. now I ask you, if the market is down in general does this generate more thin markets or less?
the answer - more(yes some get too thin and vanish). Even though RJ's cost 2x more to operate, they keep fares higher by offering fewer seats. the market forces take over and the bidding for those seats determine the viability of that market. if pax are willing to pay then it continues. an old trick/strategy for raising fares has always been to scale down in order to force the bidding to begin. I predict a short time when this adjustment will play out - it is anybodies guess (even Boyd) how it ends up. Look for mainline replacement for awhile followed by the tired refrain that RJ's are taking jobs from the mainline, then in the aftermath a revised network will appear. The only thing that skews this is gov intervention in the form of subsidies. This phenomena historically has taken the form of EAS but now many communities are buying into a local form of the same stripe.