A home stereo has to take maybe 2 channels through a hilariously blunt EQ stage (bass/treble knobs) and then up to suitable wattage for a pair of small speakers, which only need to sound right in an area of a couple square feet.

I won't get into it all unless you want me to, but a system for live performance or broadcast has orders of magnitude more work to do, functionality which is demanded by a tiny market relative to consumer electronics, with far higher expectations on reliability, flexibility, etc.

There are certainly people (Pyle, Behringer, etc) who claim to sell cheap solutions, but they are substantially more likely to bite you in the ass in concrete, embarrassing ways if you try to use them in performance environments.