Wow, that's really tough.
Every match-play World Champion excelled at the endgame, including Tal. Most World Champions were the best endgame player of their generation.
Today's best players don't have the advantage of adjournments, and yet they usually play at a higher level than even the best pre-computer endgame players (that would be Karpov, Andersson, Speelman, and maybe Kasparov).
By that standard, Carlsen is probably the best endgame player of all time. But I really enjoy the endgames of Andersson, Smyslov, Botvinnik, and Karpov.
Computers help players a lot in openings, but are useless in endgames, endgames principles are the same today than 100 years ago, so I don´t think current GMs are better than former (look Caruana missing a win with R+B vs R vs Svidler in Candidates 2016, or the horrible Queen endgames Hou Yifan lost vs Carlsen and Giri).
You Obviously don't know what table bases are. You obviously don't know that adjournments were abolished due to computers and that was before computers could even play at GM level. You obviously haven't been over many historical games, because those guys botched endgames too, and more of them. You can't simply go over the best endgames of the best players from 100 years ago and compare them to the worst endgames from players that are not the best today; and then conclude that past players played endgames as well or better. That is ridiculous.
A couple years ago I downloaded a massive pgn database from chessgames.com, which was all games that resulted in a king + rook + pawn vs king + rook. I never made it through all the games, but the quality of early chess games was astoundingly horrible.
It's an absolute certainty that past greats have unjustifiably been mythologized.
The best endgame player ever is Magnus Carlsen. This is 100% due to modern resources.
Now I don't know if he deserves credit for being the greatest endgame player ever because for me, best (absolutely strongest) and "greatest" are not the same. An example: Rubinstein contributed to the progress of rook endgames where as Magnus Carlsen benefits from previous contributions of theoreticians and computers.
Leave it to us amateurs to obsess over superlatives instead of having a genuine curiosity for the science of chess.

Wow, that's really tough.
Every match-play World Champion excelled at the endgame, including Tal. Most World Champions were the best endgame player of their generation.
Today's best players don't have the advantage of adjournments, and yet they usually play at a higher level than even the best pre-computer endgame players (that would be Karpov, Andersson, Speelman, and maybe Kasparov).
By that standard, Carlsen is probably the best endgame player of all time. But I really enjoy the endgames of Andersson, Smyslov, Botvinnik, and Karpov.
Computers help players a lot in openings, but are useless in endgames, endgames principles are the same today than 100 years ago, so I don´t think current GMs are better than former (look Caruana missing a win with R+B vs R vs Svidler in Candidates 2016, or the horrible Queen endgames Hou Yifan lost vs Carlsen and Giri).