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...

It's not being privatized because it's extremely expensive to maintain and also it's politically impossible as several modules are Japanese or European owned and half the station is Russian and there's no propulsion on the USOS side.

As to not boosting it to a higher orbit, firstly that would require a tremendous amount of energy, more than any craft currently visiting it. So you'd need to custom build something for that purpose. They're already custom building something to deorbit it with less thrust requirements than you'd need to boost it upward. Secondly the station is slowly experiencing cracking and eventually will suffer a catastrophic debris strike or depressurization. This massive object would create a massive debris cloud and putting it in a high orbit would ensure it would last for thousands of years.

There's also a political factor for why it's not being boosted, in that as long as the ISS exists governments and the public would want to see it maintained and used. Just boosting it and letting it rot would make space agencies look really bad in the eyes of the public. It's better to just decommission it and have no chance of a future salvage effort. (this doesn't touch on why not do privatization of the ISS, other comments have responded)

It's old and expensive. For example, there's a 5 year old leak that they still can't locate or even decide on the severity.

I'm sure the offer is open if anyone wants it, but that's a hard sell at this point, and the major players all have other plans.

https://spacenews.com/nasa-and-roscosmos-disagree-on-cause-a...

It is slowly becoming unsafe, and fixing it in orbit is likely too expensive. Space is a very punishing environment - enormous differences in temperature, vacuum, aggressive radiation. 25 years of such conditions will have consequences.

It could probably be dragged onto a higher orbit as a museum in situ, but keeping actual living people in there is going to become too risky soon.

ISS is being replaced by one or more semi-privatized stations. ISS is rapidly approaching the point where maintaining it costs more than simply building a new station.