Here's every mainline GT's count by my count. Only races and championships are counted, so things like missions and GT5/6s special events are not.
GT1 59
GT2 228
GT3 337
GT4 511
GT5 141 (A-spec only, it doesn't get double credit for B-spec being separate versions of the same races)
GT6 201
GTS 301
GT7 236
So from a length perspective GT4 is the longest by far, then GT3 and Sport, then 2/6/7 all kind of together, then GT5 needing B-spec to pad itself, then GT1 last which is forgiveable as game 1 in the series.
Judging a game's quality based on the number of events is stupid.
That would be stupid, but quality is not the point of this comparison, this factoid only tells us that GT7 is short. My major gripe since finishing the 39 Café books in the first week was that it felt like a very good
beginning of a campaign;
Sunday Cup -> B License -> A License -> First 5-race championship -> |Unexpected End| -> Grind.
It's structured like the first 40% of a great GT game, and if - as you progressed through IB, IA and S events - the prizes and difficulty continued to grow up to and beyond the level of the high-Credit anomalies and the 🌶️spicy races, there'd be a satisfactory experience for most players,
especially if it ultimately meant less time grinding the same race.
I think it's pretty clear that the majority of events in World Circuits are not very interesting. There are a few exceptions, but aside from these, I have mostly ignored WC events since completing the menu books, apart from doing the weekly challenges, which are hit and miss, largely as a result of chase the rabbit. I think the criticism of these events is mostly fair.
But what I find interesting / fascinating is how much people care about this. For me, these World Circuit events are more like a quick play / arcade mode, and there is so much good content outside of these events to be enjoyed. Obviously other people have not had the same experience, but between missions, licence tests, circuit experiences, daily Sport races, online time trials, online lobbies, offline time trials, offline tuning / testing of cars, I still haven't done everything that I want to, even after over 1000 hours of play. Of course this is just my opinion but the fundamentals of GT7 are so good that I keep coming back for more: the quality and variety of tracks, the quality and variety of cars, the excellent physics engine, the glorious graphics, the brilliant VR implementation. I can't get enough, and for me this completely eclipses any problems with the singleplayer content.
The other reason I don't really care about the WC events is that I am much more disappointed in the Custom Races. Given the great foundations that GT7 has, this mode could be sensational, but the broken AI and rubberbanding completely ruin it for me.
These are also important points: that the WC events are only a small part of what the game has to offer, that the physics make car testing a lot of fun (hear, hear!), and that Custom Race mode could be the best part of the game if it had more than three difficulty settings.
The number of curated races and championships in GT7 shouldn't be a big problem,
but it is, completely because of how the game is structured. Every player has to play the mandatory events first, so it's vital that the early-game leaves a good impression. Once players have finished Book 39, the only way to afford more cars is to beat the Missions, Circuit Experiences, Online TTs and... then you're back to playing a lot more of the same part of World Circuits; an unfortunate side-effect of game structure and car pricing.
If Custom Races could replace the lack of high-level events, that would be great, but they cannot.
If Sport Mode daily races paid substantially more than the Jimny Cup, that would be great, but they do not.
If saving up for three McLaren F1 variants didn't involve over 36 hours of racing the top four richest events,
or over 90 hours of Custom Races,
or 300 to 700 hours of multiplayer,
or silver/gold in every Online TT for 60/30 consecutive weeks, that would be great, but it does in this game, and I never want this terrible and easily avoidable situation to happen to GT again.
If GT7 had ~500 events at launch (including Menu Books leading to the S Licence, the traditional endurance races and a formula championship etc.) there's no guarantee that it would be a perfect game, but it would be more enjoyable, for more people, for a longer time and the post-game would be much less repetitious. Updates would be adding in welcomed extra events for variety, not the foundational parts missing at launch like Kei and Gr.1 races.