I'd agree, if someone were making injection molded display pieces for a lesser price...
Since your other options are resin, 3D printing, cardboard/stock, and hand made, I think $200 is reasonable since the figures do cost a lot already and most who are collecting them wouldn't want something chincy as a display.
I know that sounds snarky and that's not my intent. But these aren't "toys" and are also not some guy making them in his garage with resin or with a home 3D printing setup. The price is warranted, when you think about it. Though I totally get it not being in everyone's budget or justifiable. I've paid that much for a car I used for quite a while. I get it. But the "these cost too much" crowd really don't seem to be thinkibg about what goes into this and what you actually get. I'm not diving into 1/6 even though I would love that for my SS Vader. I can't afford it really, or I might. I am all into the 3.75" ones though.
Now, if Sideshow were making these and selling them for less... but they're not. Plus most of their large display items (Cantina, Yoda hut) aren't plastic. They're like polystone casts or something iirc... These, they're professionally done items, by a start-up that's a fraction the size of Sideshow which isn't a big outfit itself. They're still getting these done in a professional manner from design to final production and shipment. That's sorely missing, but these are definitely not in everyone's budget. I think though, if you're a 1/6 guy diehard, this is the kind of thing you'd be hard pressed not to sink $ into. Stormtroopers with that behind them? That's a beautiful thing!