What a load of ill-informed drivel.
I suppose you go into 'Go-Outdoors' (other 'real stores' are available) take an hour or two of their time and try all of the different brands and sizes of boots on, then once you know exactly what brand and size you require go and order them on ebay (other on-line suppliers available)
How do you expect high-street stores to be competitive when they are paying huge rent, rates, staff wages, pensions, holiday pay etc etc. Your 'on-line' supplier has a shed with a limited range of sizes and virtually no overheads.
To answer your question "who really cares ?" - I DO !!
That's a bit harsh. He's dead right that for most people, price comes first. And convenience and choice come a close second - the internet often wins on these, hence the decline of shops.
Also for a lot of people going for the cheapest isn't a choice, it's a necessity.
Where he's wrong is the greed thing. Some shops used to be greedy when they had a semi-monopoly in a town, but those days are over and now they're generally as reasonable as they can afford to me.
Re: Decathlon - I don't think you can get stuff much cheaper online. They're already very cheap. I don't see any online retailers beating Decathlon for the synthetic underwear Gunwharfman bought there. They're generally not selling the cream of lightweight gear but they usually sell well-priced gear. I've got plenty of it.