Exclusivity is of course important, the exclusivity of each console shapes the existence and value of their respective consoles, so if this rumor is true, wouldn't it be a good idea to expect other first parties on other platforms? That would only decrease people's desire to buy Microsoft consoles, and do even less good for xbox fans. It's even only xbox consoles that don't have a physical version of xbox first party. If one day Nintendo's first party comes to other consoles, where's the reason to buy a bottom performing switch? Xbox is happy to land their first party on other consoles, but Xbox consoles and fans don't even get second third party exclusives from Nintendo and Sony, how ironic.
I support xbox with real money because I want them to grow their brand and first party, not see them slap their fans and self-destruct over and over again, if this rumor is true I'll sell my Halo Infinite limited edition console.