Well HTML5 apps will never be a good experience on iOS then. On Android you can do almost anything UI-wise with Chrome, which paves the way to HTML5 installable apps.
So, I disagree entirely: iOS can easily support fantastic HTML5 mobile apps... if push notifications ever become available.
From what I remember, Google started switching to bottom tab bars a couple of years ago, even on Android. But, when you have a bunch of features, it's much easier on the developer (not the end user) to just stuff them in a hamburger menu and say "eh, good enough..."
Link that seems relevant, but I've really only skimmed it: https://uxplanet.org/tab-bars-are-the-new-hamburger-menus-91...
Push notifications would be necessary for a complete feature set too, although I don't really use them for my private apps since I disable almost all push notifications on my phone.
I think WebRTC is supported on iOS? Maybe it's missing some important features? I'm not personally familiar with what's going on there.
Web Bluetooth doesn't seem to be going anywhere fast, for better or worse.
So these features almost certainly won't be delivered, in a working state, until they are irrelevant to making useful apps which could move money out of the ios appstore.
The last time I looked they were incredibly fragile to implement on mobile device browsers. Mobile Safari had borkage: rotation or tab addition/deletion changing the page height such that you occasionally lose the bottom bar; input focus loses the bottom bar or leaves the bottom bar occluding elements (position sticky doesn’t recalc when page scrolls). Problems with strange interactions with the browsers own bottom bar. Both have problems when the page is zoomed, which seems to happen sometimes even if explicitly disabled e.g. input focus?
I could make something that looked like it worked, but when actually manually testing it hard, there were show-stopping problems.
There's very little reason for good tools to exist right now, when notifications don't, and this seems intentional on Apple's part. Great tooling could definitely exist for HTML5 mobile apps to make it a good experience to build great apps that way... except for the lack of notification support on iOS. Historically, the Google Play Store is so lax about things that there's no reason not to just submit apps there. You don't even have to give Google a 30% cut on a lot of things, if you provide your own payment mechanisms. So, making HTML5 mobile apps for an Android audience has never been that appealing. But, that might be changing soon. On iOS, there have always been a lot of motivating reasons for companies to release apps as HTML5 Mobile Apps, but the lack of notifications just completely stops the idea flat.
For HTML5 mobile websites, a hamburger menu is often an unfortunate reality, but I think having the most frequently used links always clickable at the top of the page is better than stuffing absolutely everything into the hamburger menu. HN does a great job with this.