Being completely ignorant of ongoing NASA or private venture space projects, if the Hubble telescope is so useful and oversubscribed (not to mention old) wouldn't it make sense to launch a few more Hubbles sometime soon?
http://en.wikipedia.org/wiki/James_Webb_Space_Telescope
No idea if anymore are planned.
It's a lot cheaper to build (and fix!) telescopes on the surface of the earth (in a few select locations like the Atacama desert, the Canary islands and mountains on Hawaii) and the best of current telescopes can deliver images with similar quality to what the Hubble space telescope can produce.
Perhaps, someday someone will figure out how to tap into that pile of cash for Big Science.
[0] ...or thereabouts. https://www.nationalpriorities.org/cost-of/
Edit: autocorrect.