GMs resigning in theoretically lost endgames In classical play, do GMs tend to resign in endgames like king+queen vs king+rook where the game can be won by the side with more material in under 50 moves, but only with good play? (I understand queen vs rook is a win in 31 in worst case, barring any immediate captures/checks which make it a draw. A computer can likely draw it out to 50 moves against a human, but another human might not.)
Queen vs rook isn't the only example - think of any pawnless endgame where the fastest forced mate is between 20 and 50 moves long.
On one hand I could see that it might be insulting to continue to play on with such a difference in material, where your opponent will clearly not fall for any skewer tactics and the endgame will be very long and very boring, but on the other hand I see the pragmatism in continuing play as long as there is a non-trivial chance of a draw.
They may as well try, since Q vs R is extremely difficult to win (even disregarding skewer tactics). The example of RB vs R is a great similar example, as it is a theoretical draw, but extraordinarily difficult to draw. There are numerous examples of top grandmasters being unable to convert Q vs R. As to a computer vs human- this was tested in 1978 in a special match between Belle (computer program, had the tablebase so it would play perfectly), and GM Walter Browne. Two positions were played, both with a win in 31 moves. He was unable to convert one but won the other (although barely avoiding the 50 move rule)
Example 1 - Gelfand-Svidler (two of the greatest players of their time, admittedly a rapid game. Black was pushing but Gelfand held.)
Example 2 - Morozevich-Jakovenko (Morozevich was a great player, but Jakovenko not so much. Morozevich was pushing, but Jakovenko held with what is known as a rambling rook idea, where a rook is sacrificed and keeps checking so either perpetual check occurs, or the king takes the rook leading to stalemate)
To add more to this- it's quite possible that the side with the queen is in time trouble, which heightens the difficulty of breaking through.