Even if you assume 100% of them go away - I'd wager voters in California would prefer to have current conditions improved than an ever so slight increase in opportunities in the future.
Yes - small businesses employ the majority of workers. Do small businesses from outside of California with no current presence in California making new hires into California in a given year make up even 0.1% of total jobs? No.
On the flip side - close to 20% of Californians work remote full-time. And some estimates are as high as 40% for workers that work from home at least once a week.
Is this a good policy? Who knows.
Is it going to be popular? I think so.