Unfortunately not true. The stores exist to satisfy shareholders (as with all businesses). The more customers and profit, the more shareholder satisfaction so they will work on that. If they could produce the results with less customer satisfaction they would (as you have seen) -drop service until they squeak then crank it up a bit. Look at the piles of crap left in the aisles of Tesco 24hr stores late at night because they have to stock shelves when customers are there - doesn't make me satisfied but they are open and I'm still there (occasionally)!
I'm not particularly a Tesco basher (otherwise I wouldn't shop there) but the most malign influence of global food retailers is their effect on the supply side - customers get an advantageous deal overall - the suppliers pay the price.
Bob Mannix.