Er, what exactly do you think "freely pooling together with other employees" looks like? A group of employees that negotiates together is a union.
You can negotiate alone, but you have much less bargaining power that way. There's a reason the big tech companies all work together on their side of this negotiation (colluding with other employers to lower salaries, all doing layoffs at the same time, etc.): it works.
You can negotiate alone, but you have much less bargaining power that way. There's a reason the big tech companies all work together on their side of this negotiation (colluding with other employers to lower salaries, all doing layoffs at the same time, etc.): it works.