Whilst I can see where you are coming from as many main dealers are incompetent.

Lets face it, those who sell cars are usually far less than honest and often just try and move vehicles on without spending any money on them at all other than a good clean.

There are 2 issues here. If that vehicle was sold with a valid MOT, and even more so a recent one, it does bring into question whether it was a blind man who carried out the test.
If it was an older MOT, and maybe high miles or hard usage in between, didnt the selling garage carry out any sort of inspection prior to sale ? Selling such an unroadworthy vehicle is surely illegal ?
Assuming all the suspension and brake issues are legit.

If car dealers sold honest vehicles in good condition after a proper inspection and repair...you'd never have those headaches or customers returning