Earlier quoted context omitted.
Well when someone is offered a 'key' engineering role it's basically a fancy way of saying 'you'll be building pretty much everything'. Couple that with the fact that it requires a 40% pay cut and you've got a situation that definitely warrants co-founder status.
Most founders go with no pay for quite some time. You can still be a co-founder and receive pay but being a co-founder conveys far more risk and responsibility than being one of the first x employees in the company. Even if you happen to be the person "building pretty much everything", it still does not justify being a co-founder. If you wish to be a co-founder, you typically have to be willing to take more than 40%…
That's not what I said at all.
Early employees that are paid a fair market salary are absolutely not entitled to founder status, and in some cases not even substantial equity.