What you are missing is that games, all games, go on sale eventually.
There is already a “complete my bundle” offering on the Steam.
There is no principle in your post, Purdy. Whether we are talking books, movies, games, etc. the longer they are out, the less they cost. New releases cost more.
Also, DLCs and expansions don’t “fix” anything. They add new content or new features. The base game has received over 2 years of free updates to fix bugs or improve AI or enhance UI, balance gameplay and even add lots of new features. You didn’t have to pay a cent for any of that. But if you want new features and content then yes, you have to pay for it.
Also, consider this your final warning regarding personal attacks.