Yeah, a couple of others have hinted at but not really fully explained, the OP/thread title has it wrong - it's not an opinion piece and it's nothing to do with the CL. It's an extrapolation from a German article from a Frankfurt news source.
The story isn't that we're not big enough for the CL, it's that the organisers of the Super League have now convinced UEFA to take ownership of the competition as a new first level of European competition with the CL and EL becoming the second and third tier. 14 teams to be given automatic entry and 10 to have to qualify. Lipton's "source" takes up the story from that point onwards and says that England would be offered four automatic qualifying berths, and therefore City wouldn't make the cut but could still qualify through the remaining qualifying slot which would go to league position.
Take what you will from that.
Oh, and in other news, the German source suggests that the Bundesliga could be considering ending their current rules preventing private investors/companies owning a majority of shares, so that from that what you will, also.