So it's not about what's best for the user but what's best for Apple? I wouldn't call that "understandable". All this is doing is contributing to webkit monoculture.
On the other hand, the web is mostly open for all, so most people benefit from it, not just Google.
I'd be amazed if there were more than a tiny fraction of iOS/iPadOS users (of which there are hundreds of millions) who weren't perfectly ok with Mobile Safari for their everyday usage.
[I'm probably the "target market" for Chrome (backend, occasionally frontend developer) and there's no way I'd have it on my phone. I only suffer the GMail app because they've made IMAP usage of gmail unreliable.]