I want to create a union at my work, but writing for a new job is so much easier.

I work in tech. At my previous job, I started organizing a union and got maybe 20 people out of 70 involved in actively planning and being interested. But I left my old job for this one, because I could be paid more with less work. And now there's a new job on the horizon which promises another 10-20k a year, and again, the call of more money outweighs the urge to improve the current situation. Anyone else ever dealt with this issue?