The only "non-compete" clauses that are even theoretically binding apply to stealing clients andn customers and the like so generally only apply to sales people.

This doesn't stop companies trying to include ridiculous non-compete clauses in employment contracts. It's sort of a silly pretence - both sides know it's not binding so the employer makes it sound as harsh as possible but the employee signs anyway.

At the end of your employment (whether fired or you walk), if they really want you to not complete, they have to offer you money - generally fully salary for the desired period of time regardless of what your contract states.

Do you think someone in Germany under such an agreement could work for another company that had no presence in Germany or, perhaps, the EU?

Thankfully the deal fell apart for other reasons, although I shouldn't have been surprised by any of it.

Consideration need not be during the same period. I can pay you $X today for something that covers the next N years.

(And as for why people don't just add "compensated via your salary" to the boilerplate - that's an open-ended transaction, not a defined amount of compensation for the year of noncompete restriction.)

But it's not. Inventions != copyright or code produced. If I author a book after employment they don't own the rights to my book. If I write code after employment they don't necessarily own my code or rights to it.

Yes. This is WAY CRAZY because enforceable or not it abuses the information and resource availability asymmetry between company and employee.

    invention, discovery or item of intellectual property

Seems way unenforceable to me, but IANAL.

Very much possible, but as someone else alluded to, this clause is incomplete without the rest of the agreement. Somewhere in the agreement "intellectual property" may be defined [better] and it may include copyright, and it might include terms that narrow down what copyright falls within their definition of "intellectual property" (i.e. copyright-able works which pertain to the business of the company). They don't want to own everything... what if I write software for a personal pet project and it causes damages... they would open up themselves to potential liability (unless they cover that, again, somewhere else in the agreement). The entire agreement text is needed for clarity and to make conclusions.

We can't conclude what the agreement means by "intellectual property". See comment to sister reply. We need the entire agreement text to make conclusions.

Imagine someone quit that job today, 6 months later room temperature superconductors were invented, and 2 months after that the ex-employee invented a great new use for them. It's literally impossible that the invention was made at the job, but the contract still appears to claim it.