Costs will come down, while capability will go up. I'm thinking of a some kind of box in every home, with special inference chips; not really a "PC".
In principle, every human should have access to the same level of AI. There could be one at the local library if someone can't afford one, or doesn't want one.
Which would still mean that those who can afford more/better hardware can therefore afford more/better AI. I don't think a solution lies down this path...
Is that really an issue? Eg it's the same with games, the better your hardware, the more likely you can play a new game at higher settings with better performance, with most cheaper devices outright unable to handle anything recent.
But if you wait a GPU generation or two, the performance has improved enough that you can do that with a much cheaper GPU.