Not a dumb question, official answers in [1] [2].

Summary is higher orbits have too much risk of debris strikes, and commercial operators were asked to submit proposals but NASA received no feasible proposal: they aren't interested in the ageing and expensive to maintain ISS modules.

[1] https://www.nasa.gov/wp-content/uploads/2024/06/iss-deorbit-...

[2] https://www.nasa.gov/faqs-the-international-space-station-tr...