Post 2008 (the big recession,) many out of work, older workers have applied, mainly because the job market has been so tight. (Truth be told, that was a lot of why I applied.) The government has been criticized, especially by the right, for approving too many iffy applications. So, the trend now is to set the bar a bit higher in terms of the burden of proof required. And, political pressures being what they are, that's only going to get worse.
I successfully did my own bankruptcy without the help of a lawyer, so I think I'm pretty good with paperwork. It was tedious, but very straightforward. Disability cases are way less straightforward. That's always been true.
If you are blind, or have Lou Gehrig's disease, or end stage kidney failure, then, yeah, it's open and shut. Even in those cases, the approval comes so quickly that the lawyers make nothing (in % of back benefits.) So folks with those disorders might as well use the help, since it will end up being free.
Maybe, if you've got a smart, well-organized family member to help you out, it is less over-whelming. I was alone and in danger of ending up homeless, without quick approval. So I didn't want to screw anything up.
Some attorneys will even tell you to apply on your own and come see them after you get denied on the first try. That's because they want to have your approval occur after you've accumulated back benefits. (So they make more money.) The big nationwide law firms, specializing in disability benefits, don't put you through that.
Whether you get a law firm to help you, or not, do some reading and research on the Internet. There are things you need to understand, so that you don't say the wrong thing. It is not true that the SSA wants to deny your first application just to see if you're serious. Lots of apps get denied, simply because the applicant did not understand what the SSA needs to see in the paperwork.