There are reasons. For one thing the prices listed there aren't that cheap. 2 poses=$86 etc..
I'd point out that they are cookie-cutter photos with little creativity and they'll look the same as the neighbors pix they got there.
I see those issues from "pros" all the time anyway.

I specialize in my business. The funny thing is it appears they specialize in the kind of work I won't do so they don't hurt me at all.

A bigger threat to pros is technology and lowering prices. IMO the only salvation for pros is IF they are artists. Taking a good picture technically is getting easier all the time. Knowing composition, art theory, light placement(expensive lights), post production techniques etc and really knowing your gear inside and out is what will keep us in business.

I came across a place in a mall here that makes the crap that picture people creates look like PPA loan collection stuff.
Truely horrid and you know what ... they were packed and had a 2.5 hour wait.

There package prices ranged form $12 to $36 the prints were done on epson 1200 printers AND they were bad greenscreen no effective wb nothing ...

looks like they found a market ... think about it ... if they are doing 150 to 200 sessions A weekend at $24 that is about 19K a month... even with expenses Id take that ...

There are plenty of people who eat at McDonalds, shop at WalMart, hang laser prints & posters (and worse) in their houses, and lead a generally ersatz life.

Ain't you guys ever head of Sears? They've had portrait studios in nearly every store for over half a century and are still hard at producing mediocre photography for the masses. So what? How does that effect your business? It doesn't. Why would you want to compete with, or even use their name in the same sentence with yours?

If anyone ever questions you about your prices or compares you to Picture People (or Sears for that matter), you have two choices; try to convince them you're better and worth the money, or tell them politely to go to Sears (or hell).