Moodle HQ has been pouring precious resources into 1.9 for nearly 5 years now (including the development time before it released), and will keep doing so for another 6 months. As far as I am concerned, that's a lot.
It's there, it's very stable, and you can continue to use it as long as you want. If you want to have someone supporting it for even longer, though, you'll have to rely on broader community support.
I am totally focussed on making Moodle 2.x better and better, based on feedback. File handling is one the top priorities for 2.3, for example.
About performance issues, it's really not very clear where the problems are. Many are not having problems, and some are having problems in areas that suggest poor tuning. I'm extremely keen to fix performance problems as they are identified. Petr Skoda is the component lead in the tracker of all performance issues and will deal with them.