Launch pads are not something you just buy on a whim to keep around just in case you need them. They're very expensive pieces of infrastructure that you only acquire when you have an actual, known need. That's how every launch provider that I know of behaves, including SpaceX.
Actually SpaceX is in the process of building multiple Starship launch pads in multiple locations with only an expected theoretical need.
SpaceX is "in the process" of a lot of things, not all of which pan out. So far the cases that have actually started serious construction are in Cape Canaveral, and will absolutely be necessary assuming Starship becomes operational (because the number of launches SpaceX is allowed to do from Starbase is limited).
I don't disagree at all, but I'm quite curious where the cost actually comes from. Even including all the harnessing and other hardware, it doesn't seem like something that should be a bank-breaker when we're casually talking about vehicles worth tens of millions of dollars blowing up, if not being discarded after a single launch.
If you’re NASA, the cost comes from a cost+ contract with an incompetent vendor.
If your Blue Origin, the cost comes from each launch complex being essentially bespoke and built on-site.
If you’re SpaceX, you plan ahead to use lego construction, mass produce the pieces, the tanks, etc in a factory setting, and assemble the pieces on-site for much less and much faster.