I don't see it happening on those two routes, which are almost exclusively flown with mainline equipment, and almost always completely full. Those flights also have a lot of origin/destination business day travel happening on them, which makes it more difficult to replace a 30-45 minute flight with a three + hour bus ride. There's also heavy competition on those two routes from HOU on WN, and running a bus on those two routes would certainly be conceding a lot of the passengers over to WN.