Perhaps - but they could just do what Microsoft did: bundle a version of Chromium.
Strategically it makes no sense to not own something that important.
Remember: Safari was created when Apple’s 5-year deal with Microsoft that made Internet Explorer the default browser for MacOS X expired in 2003.
10 years later. Google forked WebKit to create Chrome.
If we're going to split hairs over the whole "Blink is an inferior WebKit fork" brouhaha, we shouldn't forget who Apple sherlocked to get there. After all, turnabout is fair play.
[0] https://blogs.kde.org/2005/04/29/bitter-failure-named-safari...