Is the term GOAT a myth?

First topic message reminder :

In many internet forums, the GOAT argument comes up a lot of times. Probably once a month with peaks during Wimbledon, and post-seasons. Normally there are two ways this argument ends.
1) Player X is GOAT
2) There is a GOAT, but due to different eras, technologogy etc, we will never know.

Since 2005, Nadal has won over 200 matches on clay, losing exactly 10. This dominance has seen him win seven Roland Garros (clay) titles. Novak Djokovic by comparison has won five Hard court Slam titles, and in fact has made as many Hard court GS final appearances as Nadal has Clay. These stats would paint a picture which suggests Djokovc is a similar proposition on the Hard stuff as Nadal is on clay. Of course, this hides the very obvious asterisk which states Djokovic has double the opportunity to win on hard court every year.

This sounds like a simple, and thus simplistic opening statement, but it goes a long way towards explaining why I feel that it is impossible to determine a tennis GOAT, no matter what currency you try to use.

Clay court players have always been handicapped by the fact that they could only use their unique skills for one Slam. A major problem in the Slam race.
Grass court specialists used to have as many as three chances to win a slam in a given year. Now hard courters are in the pound seats as they could win two slams.

If the division had always been the same, then I think a justification could be made for why GS total should be all that matters. But it hasnt. It has been three grass slams, one clay. two grass slams two clay (for a brief period). Then two Grass slams, one clay, one hard. And now it is 2 hard courts, one clay, one grass.

The truth is tennis is an ever evolving game, both in terms of tactics, and the tools used to battle out. As a result, the achievements requiered to be the greatest of an era are constantly changing.
Sampras never made a Clay slam final.
Borg never won a Hard court slam
Federer has a negative record against his big rival.

In other eras, these flaws would have been death knells for their GOAT credentials, but instead, they are little footnotes in their careers.

So im closing I believe the term GOAT is a myth because

1) Clay courters are inherently limited with regards to how many Slams they can muster
2) The Slam dispersion has frequently changed,
3) The standards for a good player are always evolving (would a guy with no doubles slam even be regarded in the 50s?)

Yeah agreed there ...