Saviem, mon brave,
As usual, I am forced to agree with the reasoning of your post, except in one small area:
As a REALLY tight-fisted old ■■■■ (Welsh ancestry!) I have to inform you that Messrs Tesco, Asda, Morrison, etc. have never known the pleasure of ridding me of my hard-earned in the pursuit of a couple of spuds!
In the days before my retirement it was reasonably easy to beg half a bag of Maris product from a sympathetic farmer (yes, there are some!) but mostly I have all my days been a grow-my-own fanatic.
ALLOTMENTEERS RULE !!! 
And by the way, would your workhorse, Mr Deere, be one of the bigger chaps, with the ■■■■■■■ power plant?