This and the following image have a misguided understanding of the market. We know how this situation plays out because we ran exactly that experiment in the 2000s with Firefox and IE6. Those market share numbers are contingent on Google doing the best possible job as curators insofar as the userbase can tell.
If there are browser features that users want (like tabs) or web standards that enable Cool New Stuff (like modern JS) then users will go out of their way to install browsers that support them. Firefox got all the way to around 20-30% of the market before MS's control of the web collapsed and we entered the current era.
The "problem" that competitors of Google face is that Google is a rather competent steward of web standards. Their browser engine is hard to compete with because it is very good, their web standards are hard to compete with because they are largely appropriate.
Although I stand by a prediction I have that the next wave will be when a Brave-like model takes hold and the price of browsing the web drops from free to negative. With crypto we are surely getting to spitting distance of advertisers paying users directly to look at ads instead of paying Google to organise the web such that users look at ads.