Equity grants are based on risk, not ability.
Sometimes, very talented technical people are assuming extra risk due to opportunity cost; perhaps some other startup is offering comparable equity but has a longer runway and/or more traction. If those people are good at negotiating, they get better equity grants.
A few factors play in to the gulf between founder and early employee equity:
* Founders have by definition committed to the idea before it had any traction at all. More risk.
* Founders have spent more time at the company than employees. Each day spent at the startup, in addition to accruing compensable effort, carries opportunity cost (not to hop ship to some other company) and thus more risk.
* Founders have often worked, at least for a time, at zero salary. More risk.
* Founders that can get their companies funded, accepted into YC, or bootstrapped to market traction can presumably do that again somewhere else --- again implying they're accepting the opportunity cost of committing to one startup instead of starting another. Most employees, regardless of ability, can't say that.
It's important to remember that founding teams have drastically different compensation packages than employees do; it's almost an apples/oranges comparison. You want to remember this not to empathize with the founders but to keep in mind how different their incentives are from yours.