I'm not interested in keeping the player from winning. What I am most interested in is making the game engaging, challenging, and balanced in all situations. That's the game I want to play. You don't have to agree, but I hope you can see there are still parts of the game that aren't that way. So I advocate for changes I think will move the game in that direction, because I think the game is incomplete otherwise.
You insist players will come up with a solution to every problem. I maintain they only come up with solutions to problems the designers want to be solvable. Yes it's a sandbox game that gives the player enormous freedom... but I hope you don't think it never occurred to TFP that you can put a lip around your roof to deter spider zombies. They didn't release that feature, then watch some Let's Play videos and say "Darn! That didn't work. We'll get those crafty players in one of these Alphas!" It worked just fine, because getting the player is not the ultimate goal.
You're continuing to conflate two separate issues: your original assertion about whether a feature in a game is magical, and this second argument about whether it hurts or helps sales.
I endeavor to demonstrate a dig-and-backfill zombie spawning close-ish to you is indistinguishable from one that spawns farther away. Stay tuned.