This IP is becoming the new Call of Duty. We can't enjoy an entire year with the current game without getting a new one. TSW5 better have outstanding new innovations that couldn't updated into TSW4.
Call of duty has a much longer lifespan. There are multiple devs that rotate every couple of years and post launch support lasts couple of years. It's also completely optional to buy each iteration. You buy what you want at the end of the day.
It's more akin to sport games (Fifa, NBA,...), but instead of an updated roster, you get 3 routes, some bugs fixed, and new ones added in. Don't get me wrong, it'S a good price for the 3 routes, but at this point unless 2 out of 3 are "must have", there is not much reason to get it on day one. Both TSW3 and TSW4's base packages were on discounted very frequently.
They might as well just release a 3 route pack like they did with Rush Hour. I doubt TSW5 will have some new innovation. Even if guard mode is in the game that's meh
It's a business decision. Basically, it ensures better sales numbers. If it were a Rush Hour style pack, you could opt out of it and still get future content. This way, you have to buy TSW5 if you want any future content.
I don't think I'd go that far. There are some issues, but there is still a really enjoyable game! There's something about flying down a mainline with trees, buildings and cars mere metres away that I have yet to experience in other games.
The only COD which is the same between iterations is Warzone, which has only received one sequel over it's years of life. So, no, it's not the case that CODs are the same. I would argue it's not even the case with TSW as the game now, vs TSW2020 is very different, even if that took a couple of stops along the way.