Every year I make a point of replaying Racing Lagoon, because it's great. You should play it too. It starts out hard, use the easy mode save if it's too frustrating, don't worry it'll get better.
And when I play it, at some point I start thinking about the collective four all time great racing games that came out on the PS1 more or less in 1999. Gran Turismo 2, Wipeout 3, Ridge Racer 4 (technically '98 in japan but it's set in '99 so hush), and Racing Lagoon.
All of them feel, in their own way, a bit unfinished.
GT2's woes are pretty well documented. It was a hugely ambitious game and had a fair few bugs at launch because of the usual "gotta get the game out" stuff. But I think all of these games have some elements of that.
Wipeout 3 ended up with different physics models in every regional release, later got an "SE" version with remade tracks from the previous games, and had some bonus tracks that I believe actually were unfinished tracks intended for the game. It does feel like their original goal might have been to include all of that in the original release, plus having settled on the balance and physics details a bit.
Racing Lagoon has parts and random encounter cars that were pretty obviously designed to be other cars, and my understanding is they just didn't have time to actually model them out. Or disk space, but probably time. There's also a few unused in game items that people have found, generally just a lot of extra data saying they had even more details planned out that didn't make it. It's also easy to say "the graphics engine could have used some more refinement to improve the pop in" but that's more nebulous.
Ridge Racer 4 is easily the most polished of the bunch, but the progression is what feels underbaked to me. This could also be looked at as "they realized they had a deadline and made realistic expectations for it". To me, it still feels like it's missing something, it's just not anywhere near as glaring as the other three.
But the point I want to make is... does it matter?
Realistically, any of this stuff being "completed" would have meant either MORE crunch than was already happening, or a deadline being pushed out so far that the game might have been canceled or the release messed up. But in a purely hypothetical situation, would it make that big of a difference? All of these games are still fun exactly how they are now, warts and all. Wipeout still has plenty of tracks even on the original release. GT2 still sold in huge numbers and is widely loved. Racing Lagoon probably has the most obviously unused/unfinished parts but it's still an amazing game, and only big car nerds notice most of those shortcomings. If anything R4 leaves me wanting more the most, but only because I'd really like to 100% that game and doing so is... mind numbing.
Would they be MORE fun, like significantly more fun? Would any of them be noticeably better had the entire studio been put in a hyperbolic time chamber until the game was Done? Maybe, but I don't think it actually matters that much. What does matter is when you focus too much on the things you see as missing and it distracts from what is there.
TL;DR unused/unfinished things in games are just another instance of FOMO and you should always kill the FOMO in your head.