That quotation pops up on cycling subreddits occasionally and I've always disliked it because I think it discourages people from casual bike riding.
I've been biking to work occasionally for a few years now and it definitely gets easier.
I read that quote as speaking more to the human condition and less about cycling. Humanity has a tendency to keep pushing to the edge of its current abilities no matter how much they expand.
Yeah the quote assumes you're riding without speed limits. In a typical commute, it does get easier once your cardiovascular ability exceeds the upper speed limit given the route.