B2N2
I don't think anybody suggests the planes are illegal. Transport CofA, have to get a 50hr check and the JAR145 firm doing it is highly unlikely to be completely crooked.
The question is how bad a plane can get while still being legal for VFR training (or IFR training in VMC, keeping OCAS as far as is reasonable
), and from what I've seen the answer is "very bad indeed".
The training business is doing itself a huge dis-service operating stuff like that. In general, only those pretty desperate to fly do a PPL today, and the business is missing out on a huge pool of people (including a lot of high earners) who choose to spend their time (and their ample money) on other leisure activities.
Not that there is a real solution; there are few alternatives to the old iron.
p.s. I hope you are joking about the fuel droplet every 10 seconds! Where-ever that is coming from is seriously defective.