I'm struggling to understand why surround sound processors cost $500-2000 dollars.  Why can you get an average consumer rated surround amp for $100-$200, but not the same unit without the amplifer?

There are some really cheap, low feature units on Amazon, but reviews are not great.

We have been done lots of outdoor movies with COVID lock downs.  I have enough pro audio PA gear to support a 5.1 surround in a large outdoor setting, but it looks like cost of entry for a decent surround processor is $500.  Am I missing something here?

I think it's just market driven and economy of scale.  More customers are willing to buy an AVR with built-in amplification than purchasing separates, so that's what they make.  Anyone using separate amplification is seen as "up market" and the processors end up costing more than even an AVR with pre-out.  God help you if you need XLR/balanced pre-outs!

I read that last line and hear Joe Pesci ranting about cell phones in Lethal Weapon.