Ah come on.. in the same way you can say people would mine for less. And in fairness, nothing would happen with 50:50 share - the number of miners would decrease and so the difficulty would decrease as well.
Based on the MN payments I decided to invest about 4000 euro into 500 darkcoins I needed to get the MN.
80:20 seems fair to me and if you think MN are paying too much... well - get one.
Giving free coins, this is what masternodes really do is a very bad things for a crypto. We had 'premine', ,and now a 'postmine' equivalent concept. Masternode are nothing related to anonymity, and is not a good POS implementation, and so the word 'progres' is absurd here.
Masternodes provide the anonymity.
Proven, actual, working anonymity, which is about to get a whole lot better too, with pre-anonymised coins for everyone to spend, in RC4.