Maybe you can save a lot on the equipment itself (because it does not have to be 99,99999% reliable - those extra nines cost a lot) and thus can also deploy more equipment, and instead of a single telescope you can have several farms thereof.
So not only do we still need to have an incredibly high degree of reliability for core critical parts of the mission, that mission is now massively larger, and it's now human lives on the line if things go wrong.
Can't we still have farms of telescopes if we wanted even if a few of them don't deploy perfectly?
Can't we just have a humanoid robot go and turn the screws for us?
That would indeed be the best solution, if we can build such robots. Notoriously, computers are much better at "thinking" (or simulating thereof) than at folding laundry.
"it's now human lives on the line if things go wrong."
That is quite normal in many professions. Programmers are usually somewhat sheltered, so the very idea of risking your life on a job is shocking to them. But I grew up in a mining town and, well, some people will take that bargain for money. Some people even like the bit of a thrill.
I'm just pointing out the risk of failure and its impacts on the overall program is much higher when we're talking about humans experiencing a massive sudden depressurization event compared to a foil sheet failing to unfurl. If you think its expensive trying to get a foil sheet to reliably unfold once, imagine how expensive it'll be to design a door to properly seal and unseal hundreds of times with sharp, hard, and fine regolith constantly working its way into the seams and hinges and seals. If you think it'll be difficult getting public support after your telescope isn't perfectly functional, imagine the reluctance of funding you'll get when you accidentally kill seven people in a horrific way.