Because they barely even sell dedicated WAPs anymore and when they do it's not like you get a discount for not having the router hardware inside. The vast majority of the cost for these devices is for the wireless functionality. I get a better router using PFsense on old hardware dug out of my closet.
I dunno. I have a few dedicated WAPs. They were all a lot less than $200. I know many people who do this. Personally here using Unifi. I like the management interface, which to me is worth quite a bit. They send their logs to a syslog server on my home automation system so I can factor in which devices are connected to which AP when running tasks. Not trying to shit on you. I was just generally curious.