Its not sad at all. We've been going on 3 years with the same core books and only small mechanical expansions. Unlike say 2e, 3e, 4e, and Pathfinder which gave us new books all the time, this edition is about making our own way. Wanting to try new things and new settings with the 5e rules is perfectly natural for both DMs and players.
That is not the point of what I said at all -- so all I can actually say to that is -- whatever trips your trigger or floats your boat and as long as you are good with your rationalization of why then more power to you -- knock yourself out at rewriting the entire thing to your hearts content.