people at IBM tried this back in the mid 2000s and it never gained any traction, mainly due to employees feeling they will get fired if they say the word "union"
Engineering is a creative field where anyone at any level can produce game changing results, if well managed. Competent engineering wants (and will almost never get) is management that gets the most out of them and to be paid based on contribution. A union where everyone is managed to the lowest common denominator and paid according to age, not ability, does not appeal to anyone with talent.