Agree 100%. You can research the market, see who else is out there in your line of work, ask questions, make plans....but to make progress you just get something out there and let it loose on users and potential customers.

However this quote is referencing writing, and the author is primarily in print. Getting started is definitely key, but the kind of work being referred to here isn't typically experimented and iterated on once it's published.

And in writing you experiment too : you write things down, you read again, correct, ask a friend to read a chapter for feedback, etc...