You have to split Paradox into two parts: game developer for their own games, and published for games developed elsewhere (externally, or through independently operating owned developers). Their DLC model works well for their in-house games, because they have total control AND people play those games for thousands and thousands of hours (the EU4 joke is that you finish the tutorial at 1444 hours). If you divide the cost of the game and all DLC by hours played, it's usually cheaper per hour, if not competitive, than most other games.

In this case, the game was developed by Harebrained Schemes, which is a studio Paradox bought five years ago with projects underway. There is absolutely no guarantee of 7+ years of continual updates and DLC. You might be stuck with the game as is, and it's a flop.

https://en.wikipedia.org/wiki/List_of_Paradox_Interactive_games

I'd note the recent exceptions to the rule, which may show they've changed tactics: Imperator:Rome was a flop that they never did fix and rescue, whereas CK3 felt super polished on launch.