Not just the attorneys.
I know of two people (one possibly disabled, one a scammer)who finally got disability AND retroactive payments in a lump sum to cover the wait.
The formula is:
Attorney gets 40% of the ssdi amount from the time of original appl until ssdi is granted. Nothing after that.
So no lawyer in private practice or lawyer in congress wants a speedy process.
The retroactive payments are the trough from which the attorneys feed, on the order of 30-40%.