Re: I can choose the things I want.
No you can't. You can choose what you want from what the supermarket wants to stock. Bearing in mind I suspect their priorities will centre around delivering maximum £/cm2 of floor area. What are your priorities.
As I mentioned upthread, there are varieties of *already stocked* brands we can't get at *any* of our local supermarkets.
If I had time, I could draw you up a weekly shopping list you'd be unable to fulfil from Sainsburys, Morrisons, Asda, Tesco, or Waitrose in a single shop. And (if it comes to Ainsleys Shropshire Pea soup) not even then.
Example of market fail: Sungold tomatoes.
And that's quite before you deal with Sainsburys endemic stock control problems (ongoing since 1982 when I worked for them).
My only pause to defend the big markets is that they are very driven by *what they can sell*, which is function of fashion (Bake-off, etc). Being of Italian extraction, stranded in the wastes of the Midlands, I am well aware of how shops are forced to stock what Jocasta and Sebastian saw on "Come Dine With Me" last week. Which is also a factor in farmers markets (still no Sungold tomatoes). That's *if* you live near enough to one. (Luckily, bohemian Harborne, Birmingham, has a monthly one).