Tell that to MS Phone. Tell that to Desktop Linux. Or OS/2. Or BeOS. Etc.
A browser is a consumer product. As such the public will gravitate between two choices. 3rd place is no-where land.
Sure 3rd place can exist, but its always a distant 3rd. Trident got canned for a reason. MS phone was a good OS, but sales offered iOS and Android.
We need a stronger second option, not another option. Mozilla at least starts at parity. A new engine now is do far behind, that without Google scales of cash (which is what it took for Chrome to even join the fray) this project cannot go anywhere material.
I'm not a fan of monopolies, but all markets have a leader a follower, and a bunch of minor placings.
As a counter-point, I remember people making the same argument when Google announced Chrome. Browsers would always be a battle between two contenders and it would be better for Google to focus on helping Firefox in its fight against Internet Explorer than creating a third browser that could never hope to scrape a meaningful market share from the existing behemoths.
It’s a long road for Ladybird to be a real competitor to Chromium. However, the road to overtaking Firefox is much shorter and I’m less hopeful that Mozilla has a road to overtake Chromium.
Chrome had two benefits over IE that Ladybird doesn't have today. The first was budget, and the second was that IE development had basically stopped.
By contrast Chrome today is perhaps Google's most active development team, and has more or less an unlimited budget.
MS saw IE as a nice-to-have, Google sees Chrome as existential.
Also, while IE was very closed source, Chromium (and Mozilla) are open. That means Ladybird is competing with Brave et al for mind share, and can't play the "we're better cause Open Source " card.
Look at the mess any two-party system is comparing to where there are at least three, each keeping the others in check.