You've misunderstood the author's point. It's not about "bad judgement". The extra "rocket stage" is just another metaphor about inevitable "tradeoffs" of simplicity vs complexity.

It's a rewriting of the common adage: Every new solution to an old problem also creates a new set of problems. That's just the tautology part. The question is if you'd rather have the "new problems" instead of the "old problems". That's the cost-benefit analysis part.

E.g. Old car engines carburetors wastes too much gas. New Solution uses more complicated fuel injectors with oxygen sensors and onboard computers to dynamically control the fuel mixture. But now your new solution also created new problems of "oxygen sensors go bad that you have to replace" and "add another supply-chain dependency on computer chips" to assemble completed cars. Ok, got it... we'd still rather have the new problems of replacing oxygen sensors and adding the extra complexity of the ECU computers to gain fuel efficiency.

That's what the author is saying with his last sentence about fully understanding if the extra complexity is worth the cost: >"Maybe it's what you need to get where you want to go, but be clear about the extra weight, operational cost, engineering overheard, mental overhead."