My late father and mother used to dig around 5 acres by hand every winter when they worked for a market gardener. Effectively it was the only work for them to do during the winter, and there was no hurry, so they just paced themselves. As soon as the boss died father took the market garden over, bought the Honda F80 with a plough and never dug the land again!
I like Monty Don a lot, and I understand his message about using hand tools, but there are some jobs for which most of us are either too unfit or too time poor to do by hand. Anyway, some of us love the sound of a SIMAR and some don’t, I guess!