Those people who have skills worth money like to negociate.
The great thing about that is everone can better themselves and be worth more.
What makes you say that?
According to the first report I found via Google [1], workers who earn minimum wage make up about 2.3% of the labor force. Wouldn't that imply that almost all employees have at least some bargaining power?
Note: the report seems to only talk about workers paid hourly, I assume the statistic is no worse for full-time employees.
[1]: https://www.bls.gov/opub/reports/minimum-wage/2017/home.htm
So yes, if you can go to your boss and demonstrate your value to your organization and your value above and beyond any replacement they can find, then you shouldn't need a union. But if that's not the case and your work is in any way fungible, then a union can definitely help tip the balance of power between employees and businesses that try to hoard all the profits for the owners.