Always remember that kids become masters. Ratings are ratings and we can assume here they are reasonably accurate.
However, someone with 20K games will likely be a more crafty player. They may simply avoid memorizing opening lines but have a strong middle or end game. So overall incomplete as a player and the rating suffers.
As someone who has played many time 20K games online, I can guarantee that 20K will result in some memorized opening lines. However, what one has committed to memory through repetition may well be horrible.
In my case, for example, I still play the French.
Always remember that kids become masters. Ratings are ratings and we can assume here they are reasonably accurate.
However, someone with 20K games will likely be a more crafty player. They may simply avoid memorizing opening lines but have a strong middle or end game. So overall incomplete as a player and the rating suffers.