I don't know if I'd really call this an issue, workers at companies generally start unions because they're being pushed into untenable hours and subsistence living without an escape. When you can jump from a sinking ship and add 15-20% to your salary you're just in a very different situation. There are risks to getting serious about organizing a union, especially in tech where the vast majority shops aren't union. You could end up tied to whatever company you're at currently for the rest of your career, since I'd imagine many non union shops would blacklist you from hiring if they found out you attempted to organize at a previous job. It's also difficult to get enough people on board for unionization when almost everyone in your department likely has the option to leave for a similar pay bump. The benefits of unionization are much less tangible for tech workers, who generally lead pretty comfortable lives, than professions that are tipically unionized like tradespeople or factory workers.