And this is the ultimate downfall of a suit. When jeans and t-shirts start to show wear then they transition from street clothes to work clothes and continue to live a useful life. As for suits, well, having a tie dangling around machinery isn't the best combo. Not even during peak suit did people wear them in the field.
Depending on what you mean by “suit” exactly, people have absolutely worn them in the field for a long time and some still do. British farmers in some thick, hard-wearing tweed or felted fabric trousers, Wellington/work boots, a work shirt and depending on the temperature a more or less suit-like jacket are sort of a cliché, for example. I’m not really arguing against your point, though - just saying that it’s a bit of a continuum and there are many things between the completely impractical tie-dangling machine and jeans+t-shirt.