But heating elements are very simple parts, and I bought it from a reputable local store, so I don't really worry that I'm getting an unsafe part. It's probably going to fail in a few years due to corrosion just like the original part (we have very hard water), and then I'll swap it again.

I am not sure if that is what you mean, but to me it sounds like they might have purposefully put there so that it works like a thermal fuse.

Also, the costs were not so absurdly high 20, 40 or 60 years ago!

Huge profit margin, but you're able to produce much more cheaply than a competitor. Some would say you earned that margin, and in a fair and open market if someone else can also produce them for $10 you'll see prices start falling quickly. If they can't, I don't see how it's a "scam" for you to make money in that scenario.

Again the same strawman. There is nothing "fair and open" in price gauging replacement parts in a market where buyers cannot compare quality, reliability, durability and TCO across products, replacement parts, repair services and guarantees.

How are you not saying that they're making too much money and it's therefore "a clear indication" that it's a scam?

I'd love to be told why I'm wrong rather than just "hurr durr strawman"

Selling replacement parts with an unreasonable markup is a form of bait and switch: the customer buys the product thinking that it will have a given TCO over its lifetime. Only after some time the customer learns that the TCO is much higher when a replacement is needed.

You twisted my words by claiming that making a profit is not a scam.