How far from solving chess are we? See here: Does there exist an algorithm that would play perfect chess if given infinite processing power?

With infinite power, we could trivially recursively check every board state for winnability, and gradually work back towards knowing the winnability of the opening position.

At that point we would be able to definitely state whether perfect play leads to a White Victory, Black Victory, or Draw.

I don't know what the maximal tablebases currently are, but it seems like if you have a perfect tablebases for N-pieces, then exhasutively testing a single N+1 piece position shouldn't be that hard, and you would in the process also cross out a bunch of other N+1 positions. So the difficulty isn't specifically in evaluating positions at the next N, it's merely "there are a lot of those, and exponentially more of the next layer".

But we also have a LOT of brute-force computing power available.

How long would it take Google or Amazon to add another layer to our endgame tables, if they chose to?

How long would it take to just SOLVE chess, if humanity chose to?
Currently most of the 7-piece Lomonosov tablebases have been created. the only ones that weren't, were the K vs. K + 5 pieces. Those took about 6 months using the Lomonosov supercomputer.

Based on this answer, creating the 8-piece tablebases could take 100x the time it took to create the 7-piece, give or take an order of magnitude. Extrapolating, that would mean it could take 5/50/500 years, and probably on the lower end, 5-50 years for a supercomputer, and likely longer for Google or Amazon.

After a certain point, however, storage becomes a problem, as the number of game-tree possibilities surpasses the number of atoms in the universe. (see the Shannon Number)