This is new to me, cloning is so easy with the cloner that it only makes sense to do it this way.
I personally do not believe in degradation, dna is dna, I have never heard about apple growers talk about this phenomena. Unless they get a disease like PM . But again I would think a clone of a clone of a clone would be your best shot at cleaning a cutting.
When people say the plant has changed over the years and it's not the same anymore I think it has more to do with the grower's growing technique changing... who is growing the same way they were 5 years ago?
Finally, 2 of the most respected breeders in the US do the clone of a clone of clone thing, think subcool and bodhi. Most respected by me anyway, lol, I really like that their seeds are produced organically.
Ive got 20 moms in a baby garden right now and it's a bit overwhelming, I can't imagine bodhi has something like 300 moms / dads he has to keep cloning and transplanting, year round!
Finally, in my case 20 ''mothers'' would take way too much space, plus I only ever need 2 or 3 healthy cuttings of each, not 50....