There was a time when parking was the 'in-thing' and people actually made money out of it. With the changes that Google keeps introducing, I doubt if it is still as lucrative as it used to be. Does it mean that you need to have many domains in order to yield a good return?
Considering how many internet users install adblockers and anti-trackers today, I believe earning potential has fallen dramatically. I'm not sure it would be worth the fees to park it.