Comment 580 for bug 263435

Well except me, no one I know try to save tabs or sessions. I'm sure the Mozilla team has to focus limited resources on use cases beneficial to almost all users not just a few features here and there- same reason Opera seems to be abolishing some of its built in features. But thats why there is add-on support in the product. I recommend session manager.
And I dont know about the crashes, but even with 50+ tabs open firefox rarely crashes on me, maybe once a week.