Still cheaper for a single dev starting a startup to hook up to Firebase/AWS/Azure than hiring 'cheap' devs from Poland.
Yes but you gotta be smart here. It's not like Firebase is the only database out there. And once your product grows, and you hit Firebase limits which forces you in the "pay as you go" plan, whatever cheapness you thought you bought into quickly becomes a huge expanse.
-installing MySQL
-Installing Apache
-installing PHP MyAdmin
-running some commands from shell and SQL
-done.
If you create a startup it is wise to know the basics as such and in case that you grow to hire people to pimp it up.