An analogy: if a government provided public transportation to help ppl get from A to B throughout the city, but then some ppl increasingly began to use it to sleep on instead as a short stay hotel, or as an office for remote workers. They may even say “but I paid my fair to be on the bus!” But if enough ppl do that, then it turns the entire system into a short stay hotel or hot desk office and crowds out those who want to use the it for its original purpose. The general public (and the bus system) are harmed by this use of the bus that wasn’t ever the intention. So if ppl are unable to get to work due to busses being filled with ppl sleeping, thats analogous to ppl not being able to run nodes anymore because it’s now too difficult. The purpose was that everyone should be able to run a node at little cost. More node runners means more decentralisation, fewer node runners means more centralisation.