I really like this analogy between modern software engineering and running on two legs instead of four. At Google we half-joke that some of our internal services are at “alpha deprecated”. This is true and often painful. You can’t find canonical documentation. You can’t request a new feature that you need, because the product is no longer developed, and the team is concentrating on the newer better way of doing the same thing.
But at the same time, it gives agility. You know, that you can change things. You can rework whatever you are doing with the new knowledge that you gain. “Be prepared to throw away the first version of your product” is a good advice. You’ll have to deal with a lot of quirks on the way, but your “alpha deprecated” version might be more powerful and stable than whatever you develop with a “turtle” methodology.