[alnitak]

I second your desire for a Hubble replacement (a larger optical scope, not just an IR-optimised one like JWST). However, you don't need a new manned vehicle to replace Hubble. It only has a 2.5m mirror, something that size will easily fit inside the payload shroud of an expendable rocket.

[Monty22]

In the end, I think we'll need either a bunch of expendable type Hubbles or better ones, or moon based telescopes, which would be the absolute best possible solution.