On a more serious note.
Browsers + the web are mutually causing the degradation of each other. It can't be undone. Why would you want to support that?
The web is always supporting new questionable protocols/frameworks/standards and what not, and I have to make the choice as a user. Do I use a browser that supports all those, several hundred megabytes in size, and as secure as walking naked in the street? Or do I reduce my attack area, on the immediate expense of usability? One simple extension, noscript, is all it takes to break 80% of the surface web. If I try to harden my profile a bit in about:config to avoid some fingerprinting, even those that survived noscript get broken. So what do I choose?
Like hell. Why would I need http referrals to post on 8chan and why on hell is there no alternative to Google's captcha on 4chan. And I mentioned those image boards because their interfaces are extremely simple text-based ones that should not break. They should be the first to accommodate for a simplified web experience.
That is the web's part in this shitty foot-stomping dance. Browsers in return are all projects so big, supporting and patching up so many broken web "features"*, that there's no chance for a FOSS newcomer to produce a browser designed well from ground up while still supporting current web.
* Google takes a big part of the blame here, using underhanded methods to swallow up the browser market like always adopting new standards that break compatibility before the entire web agrees to use them, producing a never ending game of cat and mouse that fills the web with half-baked solutions.
The options I have are being either text based ones, AI-ridden botnet gateway with 15M lines of code, barely trusted but hyper-suplorted sjw furry project, hardly functional safari clones, or forks of the above.
Firefox may sound to many (incl. Me) like the better option. But that speaks volumes of how broken the web is when the best option is "awful, but less shitty than the others." Not by merit even, mind you, it's just by the sheer number of development/support workforce behind it.
So even if a superior well designed FOSS solution with large resources pops up, the devs will have to make the choice; Get caught up in this endless chase to get some crumbs out of the competition, or fight against this spiral and end up being swallowed into obscurity as your project gets deprecated by the ever changing web. Only very niche group of users will daily your browser then, those who don't mind a broken web experience.
Fork the web.
It's a harder solution. By forking I don't mean forking the frontends. I mean using the existing infrastructure to create your solution from ground up. Something modern, scalable, and better designed. Make the switch seamless and reproduce popular websites in your format. The network is already here, the infrastructure is too big to fight against. The best way is to offer a better, working mirror to it. One that does not compromise on usability, access of information, or performance, but offers a secure better designed alternative.
Offer compatibility as optional, and make conversions to "legacy" web happen on the client side.
The only way for this solution to work is with a huge community undertake, or the backing of a large company with their own interests. It's just likely never gonna happen.