By the same contrast, Bobby could've gone toe to toe with Karpov, positionally and with the many attributes that were considered Garry's plusses. Idyllic memory, tactical n combinational ability. Stamina.
Really don't see how OTB Fischer would not be heads above these two Giants.
Only thing naysayers can absolutely say is that, "he just didn't play".
Indeed.
It's all too cute to speculate how different generations would fare against a "modern" master of today. No, I'm not going to regurgitate the many reasons. Most have gone through that ad nauseom.
OTB play though, will always be the divine indicator of one's play. Whether it be blitz, classical Fischer's play has always shown to be on par with Kasparov. Limited sample sizes though there may be.