Income requirement for Highly Skilled Migrant for someone older than 30 isn't that high. According to:

https://ind.nl/en/individuals/employee/costs-income-requirem...

You should earn €4189 per month. It's not a lot of money if you are good software developer.

Booking in Amsterdam pay more than this!

From my personal experience (I don't have degree), I can say that companies like Booking, Amazon, Facebook, Google etc don't care about your degree.

If someone is handsome with algorithms and scalable architecture, then he/she can easily get more than €4K in Amsterdam.