What other motivation do they need?
Match-fixing happens in Italy, Germany etc. as well, it's just more prevalent in Balkan.
Look at this scandal, and look at the suspect. Guess who's the first one, and what clubs does he own other than Olympiakos?
2015 Greek football match-fixing scandal - Wikipedia
en.m.wikipedia.org
I'm sure match fixing happens in a lot of places, I'm sure players play for free kicks and corners as well (because you can bet on them) but to say an owner is instructing his own team to lose is just stupid especially since the result could affect their status in the Prem.
So why would the owner risk a game like that in the short term to risk his clubs status in the PL in the long term? Surely as an owner he'd want his team to stay up, if they go down it would cost him millions.
And like I said the players aren't going to down tools purely because there's no motivation for them.
This argument is dumb.