" ... as Hubble was designed to be serviced."
Well, that leaves the entire tech industry with no idea or experience of what to do with it.
NASA is seeking solutions for a way to raise the orbit of the Neil Gehrels Swift Observatory despite the spacecraft being marked for termination after FY2026 under the agency's budget proposal. The possible impending demise of the spacecraft, coupled with faster-than-expected orbital decay due to additional atmospheric drag …
STS-103 was the last mission to service Hubble. All 7 of the crew are still alive. There is a main tank at Huntsville, some SRB's approaching their sell-by date waiting for SLS and there is already funding to move Discovery to Texas. It can go via Hubble. Rebuilding the ground support equipment should cost at least $5B. How could congress say no to that?
It can go either way. Does it make sense for them to design their own bespoke spacecraft to reboost SWIFT where there's existing commercial designs? Probably not.
On the other hand, If they're planning a probe around another planet, probably there isn't an off the shelf design to use.
NASA doesn't, and almost never has, built spacecraft.
Apollo was all built by the usual set of defence contractors, the Shuttle was built by Rockwell, Hubble was built by Lockheed-Martin
Instruments on these are normally built by either university groups, or designed by university groups and built by defense companies
NASA are legally required to waste money on SLS. It would take an act of congress to end that. Putting SLS on one side, other contracts are a mixed bag. SpaceX lost money on the early commercial crew launches but made it back on the later ones. Boeing is currently $2B down on commercial crew. Commercial Luna Payload Services had a tight budget before Trump took an axe to NASA. Blue Origin was set to make a loss on Artemis when they got the contract. SpaceX are spending more on Starship than they are getting from Artemis but the work also helps them towards a really big Starlink launcher. One of the two companies making new space suits for NASA has dropped out because they cannot make a profit. Commercial LEO Destinations recently took a hefty hit too.