I did think you were going to say that actually. If they got lucky for 4 seasons why not a 5th or 6th one too?
And I'd still complain tbh, I'm the race director and seeing the exact same team win all the time isn't that fun.. anyone loved Merc domination last season in F1? Even the drivers wanted a bit closer racing.
And what's to say that they will be lucky? If you nullify their money advantage, through means other than arbitrarily drawn up and oddly specific rules, then there's much more of a chance that OMR won't dominate.
If you are hell bent on punishing them for being lucky might I suggest playing around with championship ballast? At least that way there is some historical precedence in real life touring car championships and then it comes across a little less like you're a bit of a sore loser, no offence intended mind.
I appreciate OMR's success might not make the most interest racing, but at the same time I don't think it's entirely sporting to complain about it constantly and draw up rules to deliberately hinder them. I've always disagreed with it when people called for Mercedes/Red Bull/Ferrari/McLaren to be pegged back and I disagree with it here.