Lol - love it!
However, I'd suggest that four in North London alone isn't too bad! Also, you may need to broaden your horizons a little and venture further north, as the trust me, the scene is rather different up there, and I have my reasons for that.....
No, in that area I don't think it will, simply because the buying habits of the majority of their customer base lie too much in the mainstream, therefore in terms of sustained supermarket sales of vinyl, I see no real future in it.
Lol - the country's buying habits don't revolve just around London, you know!
Near me, the Chester and Shrewsbury branches have shelves full of the stuff... I haven't looked elsewhere, as I prefer giving my business to the smaller shops.
I think you need to get out more and see what's happening around the rest of the country - take your wife for a nice weekend trip away, and leave her to browse the shoe shops while you enjoy finding evidence of what I've been saying
See what happens when you apply a little more thought...?
In my experience, a lot of the older guys who've been in the business for years are a bit jaundiced and 'burnt out' with the whole thing, and also out of touch with the scene in a wider context, and so fail to see the bigger picture. Often they don't stock the right kind of music (or even know what that is) in order to attract youngsters in the first place!
If the shop is full of Steely Dan and The Eagles, then it stands to reason that's only going to attract a certain type of customer. Not saying your guy is like that, but a lot of them are, and simply too stuck in the past. You need to major in the likes of indie, R&B and dance music.
It's not so much happening with teens, IME, but more in the 20-35 year old age group, and of course above.
Marco.