But Apple can't just pay-up every cross-platform software developer. Smaller developers will have to re-evaluate whether macOS remains a viable target platform for them. Which can translate to a dev-gain for Linux. The catch is that Linux is in much better position to translate an influx of developers to an influx of new users: Linux runs on what you have, while macOS requires you buy Apple hardware.
And let's not forget about macOS as a gaming platform. Linux has made a huge leap forward with Steam Proton. On macOS there's still a ton of games not supporting x86_64 (Catalina), and situation won't get better by transition to ARM.