On October 7, California Governor Gavin Newsom vetoed AB 446, which would have made it somewhat easier to qualify a new party. Here is the veto message, which exhibits ignorance. Governor Newsom seems to think that reducing the number of signatures to qualify a new party from 10% of the last gubernatorial vote, to 3%, would create lots of new parties. But even a 3% petition would be 373,928 signatures. Probably if he had signed the bill, no new parties would have qualified in several decades by the petition method. The petition has been at 10% since 1937, and in all the 84 years since then, only twice has any party used the petition method (Independent Progressive in 1948 and Americans Elect in 2011).
Very few groups use the petition to qualify. Instead they use the alternate registration method, which requires registration of .33% of the total state registration. The bill did not fundamentally change that route to the ballot, so the practical impact of the veto is not much.
The veto message correctly says that when new parties get on the ballot in California, that increases the burden on county election officials because it forces them to print up more types of primary ballots. The answer to that objection, which is a reasonable objection, is to provide that new or small parties should not have a primary. Very few states provide small qualified parties with their own presidential primaries (which are the only kind of partisan primaries still in existence in California). In the past, bills have been introduced to provide that small parties should not have their own primaries in California, but those bills did not pass.