Ohh ok. So it's because these people rarely commit to it, not because Bethesda is ULTRA selective?
There's that, but it's mostly because they're quite selective. Todd Howard has said many many times that there's a specific culture at Bethesda you need to fit into if you're going to work there, i.e. you can't be an arrogant ass. Not saying you are, but there are plenty of people out there who are. They also hire very slowly. Their team size only increased by 30 in the few years between Oblivion's release and now, and you can bet that only a handful of jobs there are for programmers.
Honestly, this forum isn't going to help you determine how stable your job would be with Bethesda. This is a place where fans talk about the game, and developers rarely come online, other than to answer questions posted in the Ask a Dev thread or something. Plus, even if a developer did come and post in here, they aren't exactly going to tell you anything bad about their job. The best thing for you to do is either email Bethesda or call them or just submit your resume and hope for an interview, because you're not going to get any concrete answers here.