Why some Skins are disappearing?

[burstman0]

I noticed that some sets for some heroes are not available anymore.
Why is that?
it's because the author of the models don't got credited or paid in percentage for the donations?
Or you don't got permission by they to use them?
Or it's because the skins retired don't work correctly?

[DracoL1ch]

usually because author dont want to see them being used

[burstman0]

That`s sad, Although you could convince the authors for it if money. I'm supposing it.
"Usually"? So there are less generic reasons for the retirement of them, could you please tell the other reasons?

One more question, the users who donated for the retired sets, what are they getting now?

[DracoL1ch]

no, those authors dont care about money at all
sets which were obtained before getting called out stays