The game has gotten continuous updates increasing the scope, mod-ability, stability (to an absurd degree, even cross play between Switch and PC), target new platforms (it runs on Apple silicon natively now and they did a whole bunch of work to make it work well on steam deck), etc. of the game for those same 3 years. Yes, they did come out of early access, but their approach to the game hasn't changed significantly and it continued to get better with time.

They could have called this game done way earlier and released the work they've done since as DLC, but they didn't. Instead they have massively increased the value in the game over nearly 7 years since initial early access release at $20 and have since raised the price a total of 75% to reflect this. They even gave advance notice of the both price increases.

Wube is still working on the next release of the base game, and are also working on an expansion they say will be as big as the base game. Perhaps your argument against price increases holds sway as the expansion isn't being added to the base game, instead it will be $30 (or maybe $35 given the base game increase).

I have played this game far longer than any other, and keep coming back to it when it updates or for new modpacks which completely change the experience. I would gladly pay $35 for what is in the game right now. I can understand if the game isn't for you or the price increase turns you off, you don't have buy it. In fact, unless you can afford to not sleep for the next 3 days you shouldn't, as the factory must grow and you are running low on iron.