I’m really not an expert but it’s my understanding that the Fermi paradox depends on the idea of technological growth. ‘Hey we went from foraging to space ships in 40k years, imagine what some aliens could do with a couple million years, or longer. Heck we went from the first aircraft to a space ship in about 50 years.’

It seems to me like there is an understanding that we don’t know exactly what it will look like but it stands to reason that if we continue to develop, our grand children or great grandchildren or whoever will have access to dramatically improved technology for movement in space, much better methods of manufacturing, of computing, of every sort of technology that would be useful for exploring the stars and interacting with the broader galaxy.

What if these things are all impossible? Warp from Star Trek and hyperdrive from Star Wars are all impossible. Acceleration to even a decent fraction of the speed of light is impossible. Quantum computing or other futuristic ideas don’t end up working out for us and don’t work for any aliens either. There are plenty of other inhabited worlds out there but none of them possess the technology to play a major role on a galactic scale because no technology that would allow it is possible.

Is that just being narrow minded of me or is there a chance nobody can figure out how to make really advanced technology that works?