I really like this way of thinking. For entrepreneurs, you could even go far as "all the work" being to subtract all the key risks/unknowns.

It's not about building a product (i.e. writing code or designing/manufacturing physical stuff), it's about making a list of all the reasons your idea won't work and then subtracting them all as cheaply and quickly as possible.

This is definitely something I wish I could back and beat into 20-year old me. It would have saved me so much time and effort between then and now.