The "Almost" Best players of all time

rating is strength based and its is very clear that you strength decreases if you do not practice. Look at botvinnik, he essentially used the first match as a training match then came back to win revenge matchs.

Yes, and a rating system where all players keep their ratings would let players like Fischer and Kasparov keep their ratings "forever", and it just isn't possible that Fischer would have been playing 2780 chess around year 2005.

Some years of inactivity will usually make a player lose strength, even if Lasker seems to be an exception. It's hard to see him as #12 when he won S:t Petersburg 1914. Chessmetrics ranks him behind players like Tartakower and Teichmann at the time. But such things are unusual, and today a player can't take a longer break and return at the same level (as for example Kamsky showed).

there is also a difference in accuracy,.. but this is just an refinement in the game. every sport has been refined over time. players are stronger etc. You have to consider results . Lasker is amazing to me for that reason, he understood the mental game really well an would play the person as well as the board. Lasker matters is a great book!.

Bronstein, Kortchnoi, Ivanchuk are all amazing players that  have won multiple tournaments but never the big one. (although i think kortchnoi was robbed via politcal pressure)