I really don't think people appreciate the marketing reasons why going back to one block a year is a non-starter. Let me make a comparison to Magic's closest direct competitor: Hearthstone launches three new expansion sets each year, each of which has a complete creative reset, a brand new set of mechanics and themes, and the expectation of a near-complete metagame shift driven by brand-new types of decks emerging. That's what it takes to keep people interested and to ensure lapsed players or people who are potentially diving in have good breaking points to invest at.
The Magic equivalent isn't an expansion release, it's a new block, because that's when all of the things that lead to player fatigue get reset: the prominently-focused themes, the mechanics, the creative treatment, the types of decks being successful. If you go back to doing that once a year, there's no upside case (nobody really goes OH BOY I'M PUMPED FOR THE THIRD EXPANSION even for the most popular settings) but a big downside case where people check out. You think people got mad about standard now, imagine a world where Cat hit the scene and there was another
nine months before a non-Kaladesh expansion was going to come out. Even in older eras with little competition and minimal online communication this was a huge contributor to major dropoffs of business; today, with tons of great competing products and the internet making everything feel older faster it would be a disaster.
You dump your mechanics wholesale twice as often.
Which is the reason to actually follow the trendline set by Kaladesh and max out at 4 mechanics a block ratherr than the eleven in BFZ block, not to go back to a model that makes people suffer through a full year of even the most half-baked block ideas.