I'd say it's a retcon of sorts. The funny thing that I think people don't talk about is that Toriyama has done this in less obvious ways even as far back as Part 1.
Taopaipai was still talked about in a legendary status even in the 22nd Budokai, despite the fact that many would have assumed he has been surpassed by most of the competitors in that tournament.
I'd say even Roshi may have been narratively buffed during the RRA arc, just based on some things like Goku saying to Karin that Roshi was the best fighter he ever knew (after getting stomped by Tao). And saying Goku ''may'' have already surpassed him, as though it wasn't an obvious thing.
I don't think Toriyama ever conciously thinks about these things when it happens, it's just what feels right in the moment. Roshi as Goku's mentor can't be surpassed too quickly, Taopaipai was the first major threat that decimated the protagonist, and with Kaioshin I believe he wanted him to be the weak link among the Saiyans who were steamrolling through everything, easing the tension before Majin Buu wreaks havoc.