There is zero evidence that forming a tech union would be successful and result in more pay compared to non-union workers. The first thing to go when people unionize is RSU based comp, which makes up 50+% of income for high income tech workers.

Forming a union is an antagonistic action against a corporation. You’re literally forming a cartel controlling one of their critical supplies (labor). There better be significant upside to burn that goodwill because all comp changes going forward are going to be shitty tooth and nail negotiations for salary bumps and RSUs will be kept for management only.

People at the big tech companies are looking to make life altering money and that comes through RSU accumulation and appreciation. That means being aligned with shareholders, which is the opposite of a union. The only place you might have success drumming up support for unions are mid to low tier tech companies where people make a low 6 figure salary and next to no equity.