In my experience with child and adolescent assessment, some school systems are really motivated to avoid assessing kids unless they absolutely have to (super pushy parents, really egregious behavior, etc.) because they don't want to have to pay for accommodations based on those test results. Districts are strapped for cash, so I get why they're looking to cut expenses, but it's very unfortunate.
As a result, parents who can't afford independent testing have a hard time getting services for their kids. And the parents who can afford private testing end up shelling out what seems (to them) like a lot of money - $1200-2000 in my area. I think that some parents get the idea that, because they're paying out of pocket, they're entitled to a diagnosis, so there's pressure on psychologists in that sense. In fact, I dealt with at least one parent who explicitly stated that she was paying our clinic to qualify her kid for services. Luckily, her child actually did meet criteria by about a mile, but I can only imagine that situations like that can get pretty annoying for people who do assessments.