The way you are presenting this it is as if we only have two options:
a) we give all the power to the union leadership: and suffer strikes every other day because an unreasonable and very powerful union leadership orders it, or
b) we give all the power to our bosses: and suffer poor working conditions, bad pay, hard working hours, loose our paid leaves, etc.
Frankly if these were the two choices I would pick option (a). Seeing how things turned up for America after they abandoned their unions, a strike every other day doesn’t seem too bad.
However this dichotomy is false, there are more options. A union doesn’t need to be unreasonable and powerful. A good union leadership will extend the solidarity to all workers (not just their members), and my experience with a striking workforce (the European country where I’m from also has a strike “every other day”) is that the leadership usually considers the wider implications. For example: striking kindergarden teachers are perfectly aware that they are needed for for other workers, which is why they usually try as they can to minimize the impact of the strike for non-member working parents.