I personally believe there is a theoretical limit, (which isn't 0.01) but it is likely it could only be achievable with new techniques, the techniques could just be alg sets, but it could also be like look-ahead, where with alg sets there is a visible ending, and is pretty straight forward to learn, but with look-ahead, its more abstract, having an unknown skill limit, (possible infinite? Don't quote me on that) and world class is constantly getting better at it, (I'm going to call it progressive-techniques from here on out) so perhaps to get to the Speedcubing limit you have to get to the end of lookahead and other progressive-techniques, and maybe also alg sets with thousands or tens of thousands of algs.
But that is only thinking about CFOP, there may be a CFOP limit, but new, better methods may be created, which are WAYYYY harder to learn and could be one large progressive-technique or multiple/all steps could be progressive-techniques, (not quite sure how either of those would work but I assume you get the point) I'd call these progressive-methods, or y'know the new methods could just be better, no innovation involved, or also different forms of innovation.
My point is: there is probably a theoretical limit, reaching the theoretical limit could take more time than a life-time could afford, and to merely be able reach the practical limit it could take a very long time to realise the methods/techniques required. (I spent more time on this paragraph than the last paragraph, goes to show how bad I am at formulating my opinion/point.)
I used to ponder this posts question when I was into cubing, and I came to the realisation of "Does it even matter?", if WRs are unachievable, doesn't mean it stops you from progressing, and if you become world class then win worlds, you don't need WRs. The beauty of cubing is that its never the same, the chances you get the same scramble twice is second to none, and times are inconsistent, it'll always be different, you'll never see a A05 that is the exact same time 5 times, probably not 4 times or 3 times either.
This was too much work for my brain before I even had breakfast. Also just realised the post says Speedcubing, never mentions 3x3, I'm assuming the post refers to 3x3.