In a perfect world you'd support GTK and Qt. In real life, you'd offer *something*, even though it wouldn't please everyone. If the community has a somewhat-working solution for GTK, consider bringing that into the fold. Linux fragmentation is a real problem, but it hasn't stopped competitors like Flutter from offering their own first-party Linux support. (And it's not like the macOS conversion is perfect--it goes through Catalyst, which has it's own quirks.)

Bottom line: Microsoft's decision is understandable, but it could affect the way people perceive MAUI and hurt its adoption, even though the audience that actually needs Linux support is small.