This was always one of the most important considerations: Will technology capacity grow faster than node demands? If we tip in the direction of "ever more expensive, with time" even just a little bit, it could be extremely bad on a 30-50 year timeline.

There is no possible way to perfectly balance, our only chance is to be extremely conservative and err on the low cost side. Bitcoin node costs must always increase slower than technological capacity. If it can, then running the validation software for the entire system will only get easier and easier & keep the global monetary system secure indefinitely, while our ability and improvements to more decentralized communication networks, encrypted and private communications, and new protocol layers will compound Bitcoin's ability to stay securely independent.