This is a different take on things (I think!) but bare with me.
One of the things which kept the teams close in the past - in my opinion, the key thing - was that so many cars were using the same engine a la the Coventry Climax and the Ford Cosworth DFV.
If Red Bull get a Merc engine, as has been rumoured, that will mean five teams on the grid will be running that engine. Presuming that goes ahead Merc now effectively the 21st century equivalent of these old engine companies? While I like having Ferrari, Honda and Renault in F1 shoud we welcome this kind of development? We saw at Silverstone that the Williams can, in the right conditions, match the Merc on pace. If this becomes the case for more teams, surely that can only help improve competitiveness in the long run.