It is more easier to secure revenue/funding from Google once they retain existing market share and gain more. They need to improve the product for that to happen.
With all the distractions they are abandoning their primary product and they are bleeding whatever miniscule market share they have. This means Google has more leverage over them and can eventually stop the funding once their market share drops beyond a threshold say 0.5% because we all know antitrust is not a strong reason anymore to keep FF alive based on trends of recent rulings.
If we're being completely honest, improving the quality of the product would not meaningfully improve their market share. That worked in the early 2000s when the competition (internet explorer) was utterly stagnant and the internet-using population was composed predominantly of techies willing to try new things. Browsers are commodities now, and most people aren't going to try a new browser when they're already using Chrome / Safari on their mobile device with all of the integrations that are available between the two.
Chrome gained marketshare not just because it was a good product but because they paid Adobe, Oracle, and legions of freeware antivirus providers lots of $$$ to put a checked-by-default box in their installers to install Google Chrome and make it the default browser for anyone not paying enough attention to uncheck the boxes, and because they targeted Firefox users visiting google.com with popups advertising how much better Chrome was. Mozilla could never do that and they would be excoriated if they tried. And as I mentioned, many of the aspects of Chrome that were indeed superior, were met with kicking and screaming when Mozilla tried to follow, e.g. choosing performance over the XUL extension ecosystem.
Sadly I think their best hope to regain marketshare is to indirectly benefit from Linux to capturing marketshare from Windows.