Sockets from a big box store should easily last decades. Eighty year old plugs will not have the ground lug and still retain the two spades. You mentioned a trailer so maybe it was wired with Huang Lao sockets and they fucking suck. I'll concede that NEMA sockets have to do the whole contact the spades correctly part well for them to function properly. True Schuko plugs separate the retention function from the electrical contact function.>bro just replace the socket every 5 years bro get really bougie pinchy pinches in them so they pinch tight bro
like how do you not understand this is a fundamental design flaw for a shitty fucking plug? better plugs exist. they don't have this issue. there is no concept of a loose plug in the eu.
Now going to call bullshit on no loose plugs in EU, having personally experienced them:

Worth saying there are in fact five different standards that match the pin spacing so many universal cables aren't the nice lock in circle.
I have not said that the good old NEMA 5-15 was somehow magical and without flaws, only mocking Europe for being Europe. Schuko is a good plug, 16 amp capacity, optional polarized/ground, durable, if a bit big. Naturally, the German design is good and the French ripped it off. Britain's debauched creation is a bloated, foot murdering mess with pointless redundancies like a glass fuse in every plug.
The American NEMA plug is small so plug density is great, carries 15 amps, has a century of forwards compatibility, is compatible with both polarized and none polarized equipment, and extremely adaptable to all sorts of form factors. It also has about three critical dimensions, length, spacing, and height of the spades while the Euro has everything dimensioned perfectly inside a circle. German design, naturally.
Engineering is tradeoffs, not perfection.