Yeah - I take it back - I spoke too quickly. You can certainly launch large satellites with rockets. I was too focused on Hubble specifically.

That said, I remain deeply skeptical of the idea of being able to do so cost effectively or in a way that allowed for iteration and development of the systems. That's a lot of eggs in one basket to make 4 duplicates - they'd all fail in the same ways (which Hubble did early and often) and they'd be space junk in a heartbeat. You'd also want different cameras, which would have different requirements, etc. Once the contractors got a hold of that, they'd wind up 4 separate projects costing a fortune, and you'd be right back where you started, except without the budget. Keep in mind how long it took to build the HST. A servicing mission turned around in about 3 years.