I'm looking for a good all round microphone (discord, Skype, Gaming, …)
why are many microphones compatible with almost all devices except Xbox?
Most microphones have the following description: compatible with almost everything (except with Xbox)
why is that? And what will change with the Series X? Are the microphones compatible with the Series x? Who by chance knows that?
That's Microsoft's problem… Almost nothing is compatible with the XBox and you always buy the originals.
The Xbox is similar to Apple products.
Hardly anything is compatible and you are forced to use the more expensive hardware provided / prescribed / recommended by the manufacturer.
Whether it is due to sales that were believed to be lost, or whether the "fear" is too great to have to admit that the in-house goods are inferior to the cheap competition, the fact is, those who are only informed afterwards are often left with higher costs.
Stupid question maybe, but isn't Microsoft and Windows identical? So aren't they at least partners? What's the point of a device working on Windows but not on Microsoft?
Microsoft is the company behind Windows and the Xbox, that's correct.
Usually only the manufacturer knows the meaning behind such an incompatibility, it may be because more peripherals want to be sold to the actual console.
But it can also be because the system could not be compatible, but Microsoft might not want to flood the market with cheap providers and rip off customers with inferior goods and leave them dissatisfied.