To use your example, here are the options:

• today we can definitely get a Union that covers some tech workers but not all of them.

Or

• today we can try to get a Union for all tech workers, but it’s a long shot. And if we lose, the consequences are that we don’t get another union vote for 4 years and during that time, the tech companies get to run rampant with negative propaganda about unions, making the challenge even harder next time.

Which would you choose, second largest tech union guy?