Property is one of the contribution to high inflation. Property price up, rental up, price up. Consumer spending power decrease overtime as income is stagnant, then those shop cannot sustain their business as their expenses goes up but not their revenue.
Those shops where the business is good, landlord will also increase their rent, those who already made their product famous, will just move out to cheaper location. Landlord suck thumb and look for new tenant or try to duplicate the business which usually fail.
Having stayed in SS2 areas for some time, what you've noticed is not new, just that it's getting worse.

Greed =