They haven't done anything illegal or immoral. Giant company tries to use nonsense lawsuits to illegally destroy competition doesn't make for great PR.

Yeah, if they took the path of ARDI's Executor from the 90's, it IS possible to have a completely clean-room emulation (of Apple) without violating any intellectual property.

They are no threat to Apple; Apple's business is selling hardware, with software bundled to it.

This is no more menace to them than ReactOS for Microsoft.

A natural pivot if the software was successful would be to start selling the hardware with the software putting them in direct competition. After all people generally don't buy OS they buy computers.

Exactly. Do people sell computers with ReactOS?

OTOH Wine, properly improved and adjusted, sort of made a dent in the market in the form of Steam game consoles.