If you are trying to make money and ship a product, then I have seen far worse than just a Front end and a Firebase. Go for it. Get your product in front of paying people as quickly as possible, then sell sell sell. You'll probably fail (the default state of a start up is failure), but you'll learn a lot along the way.
If your hope is to learn how to write code for other peoples products and have them pay you, it would benefit you to get a more full stack education. Node would be good. Rails is nice. Django is nice. .Net works well. Java is good.
If your hope is to learn how to write code for other peoples products and have them pay you, it would benefit you to get a more full stack education. Node would be good. Rails is nice. Django is nice. .Net works well. Java is good.
It just depends on what your goals really are.