This point has been beaten to death here and elsewhere. Roger Federer also has been desperate to win an OGM, but had he ever won one in 2004, '08 or 2012 he wouldn't give one damn. Just like with Davis Cup, once he won it, he never played it again and never mentions it. The players themselves highly esteem an Olympic medal, no doubt about it. But that doesn't alter that for tennis legacies, it counts for just about zero.
Well, Nadal won the OSGM in 2008 and played the Olympics again in 2016 (would have played 2012 too had he not been injured). Murray was just as eager to defend his OSGM in 2016 as he was to win his first in 2012 so the idea that players win one and then forget about it is just laughable.
Who even knows who Rosset or Massu are?!
I'm not sure what point you are trying to make? Who even knows who Gimeno or Costa or Gomez are and yet all 3 won Roland Garros. Does that devalue it as a tournament?
Agassi has one and nobody ever mentions it. His big career achievement was obviously the CGS.
On the contrary it get mentioned all the time in descriptions of his career achievements, albeit after his Slams of course, and gets mentioned all the time on here whenever anyone tries to make the case that OSGMs are meaningless in tennis usually by fans of playes like Federer and Djokovic who have never won one.
Andy Murray's obituary will read in 70 years:
Sir Andrew Murray, First British Man to Win Wimbledon in 76 Years, Passes Away Peacefully in his Sleep at the age of 100
His Gold medals will get a passing mention halfway through the obit.
Slams are always the pinnacle of a player's achievement and Wimbledon will, of course, always be cited as the pinnacle of Murray's. But so what? Does that devalue all the other tournaments he and other players have won just because they don't match up to a Slam and, if it doesn't, why should their Olympic achievements be treated any differently?