All queued up for another lap then?
It seems to me there are two strands to the seemingly endless cycle on here. Firstly there's a tendency to divide people into Bad People (yuppies, hipsters, newcomers, anyone who's bought a burger at any point) and Good People (old skool Brixton). The line is never going to be clear though and it's always going to result in endless bickering and accusations of hypocrisy (sometimes quite justified IMHO). It gets people's backs up and it's not really a very useful explanation of what's happening IMO.
The second is what tends towards a pure free-market argument. People's money is their own and they can spend it on what they want (some of the people involved would deny that's their view I'm sure but that's essentially how the argument functions). The end result being to ignore (or disregard the importance of) the very real changes that have been going on. 'But Bouji's South is only slightly more expensive than Champagne and Fromage, what's the problem?'
I think it would be helpful to be able to look at people's behaviours in a way that doesn't put them into groups quite so much. So to take Honest Burger, say, is everyone in there a terrible person, waving their bundles of cash at the poor? No not really. They're just in there buying a burger at a price that isn't beyond the means of most people, some of time at least. It's not an unreasonable way to behave IMO. But is the place a gentrifying influence? Yeah, it clearly is. Is it possible for the thread to look at that without there being a fight? Dunno.
I'm not taking the Champagne Bar as example though because that is taking the piss a bit.