This happens to me consistently. Launched an app last month and I now have daily emails of studios asking me to hire them.
Many of them don't have anything close in portfolio experience to what I have. Some of them want to charge outrageously cheap rates (but only for volume) - but being a lean one person startup, tbh, I can't really afford them.
How do you explain to others (especially studios) that despite the success of said app, you're just a one person studio (also, financial success is not quite there yet)... you can't really afford to hire them, and might sometimes appreciate it if they share jobs. (Actually, generally, I am very picky on what I take these days, so it is also unlikely that I would be interested in their job.)