I mean, that is basically what Alpha game development is. They are still designing the core features and mechanics of the game. It is the time period in development where you try something, like it or not, and then try something else if you don't like it or get a different idea about how you want the game to be.
One of the main reasons for changes to loot balance, locking things behind gates with the magazine system, and jar removal, is to extend the gameplay of the game. It's to make it take a bit longer for you to become heinously overpowered. I mean look at Alpha 16. You could be fully equipped so no horde was a challenge in just a couple of game weeks. People were complaining that the game was too easy, that it got boring too fast. So the developers decided to stretch out the initial gameplay to a span of 30 hours. Now they have decided to make that closer to 50 hours.
And unlike many other studios, TFP has made it so that most of the previous Steam releases are still available to you. So if you liked a16 the best, you can keep on playing it.