I've really not ever noticed this happening on a significant scale.
The only one egregious example I can think is Ni no Kuni II.
Game came out promising fairly large updates shortly after launch. Game was released March of 2018 and the first "substantial" add-on came out December 2018, a full 9 months later and the 2nd one was March of 2019 a full year after the games initial release. A lot of folks moved on from the game after that point.
Tecmo Koei is hit or miss. Stuff like Nioh 1 and 2's Season content was excellent, adding entirely new story chapters, new enemies, increasing the challenge adding new difficulty levels and even raising the level caps for each additional new episode.
While the inverse you have Dead or Alive 5 and 6 which is multiple season passes all costing more than the $60 MSRP of the game, most of it comprised of mainly of cosmetic DLC, I think DOA5 alone had over $1000 of DLC, across 7 Season Passes, also there was content not even part of them too. The only thing that is comparable is probably some FP2 mobile gacha game, not from a $60 MSRP console title.
It's a shame not every expansion pass / season pass is like Mario Kart 8. The base game had 32 tracks across 8 cups. The Expansion Pass added 16 more which is equivalent of 50% of the games track count at launch, pumping up the totals to 48 tracks in all, the largest in terms of variety in the series to date. The most notable thing though is 25 of the 48 tracks are all entirely new. So the updates were substantial with the majority of being new content despite the remakes of older tracks such as SNES Rainbow Road for example.
