Hello & welcome to the forum.
Your system far exceeds the game requirements, as does mine. I don’t get frame reductions as drastic as others with lessor specs. The game is poorly optimized, and the lower end computers just simply can’t handle this game well. Many have reported frame issues that make the game crawl along. One of the more notable areas was the SF Bridge, and other highly congested places. Therefore computer hardware, and the poor optimization of the game is certainly an issue.
The ones that actually get the game to run well, seem to like it. I know I do. Trucking sims aren’t for everyone. There’s no need to belittle people that are interested in these types of games as your last remark seems to imply. It’s a matter of taste.