Speaking for Canada, other fringe parties have formed over our history. Most disappeared. Some merged. A few became serious influencers.

I will say that it takes a bit of work to get a new party registered and on the ballot in Canada. Many signatures and a reasonable amount of $$$$ to register. And lots of forms to fill. And certain obligations after the election to remain legal for the next election.

For many years, Canada has had the satirical Rhino Party. It has no intention of winning any elections.

https://en.wikipedia.org/wiki/Rhinoceros_Party

The winner-take-all contests in the USA (and Canada) put fringe parties at a disadvantage. Voters who may support a fringe party fear their vote being wasted as their second choice (the credible alternative) tends to lose that vote. We call this "strategic voting."

A ranked choice vote would cure stategic voting. For example, an leftist American could vote Green, giving the second choice to the D's. But neither the D's nor the R's want this arrangement.