If I release 1.0, then add a couple "medium" size features and release as 1.1 a month or so later, I can keep doing this indefinitely with 1.2, 1.3, etc. Baring some truly some new big thing or a fundamental change in functionality, it becomes very unclear as to when to release "2.0" or what even makes it different than the other 1.x releases.

On the other hand, if I do the exact same work of adding a couple features per month, but don't actually release, I could then make a big splash a year later with 2.0 that had 19 new features, and I think most people could readily agree that qualifies as a "major" release.

From a quality point of view, release early, release often is very useful: get feedback quickly, iterate in small chunks, minimize breakage.

However, from a marketing point of view, this is boring -- especially by the time you're on 1.19 and your features are largely quality-of-life or only affect a small segment of the market. A big 2.0 release that gets press releases and such is much more exciting.