In fact, there are posts on this forum asking for levels beyond 20:
Even then, way back in December 2015, a poster said “in many games like Diablo 3 the leveling up never ends.” while another notes that there was a previous increase from 15-20.
OK, Zwift was still in beta at that point, so I guess Eric’s article is only talking about once Zwift was out of beta.
Point is, this has been an ongoing issue for 9 years!