And just to be clear, it's not that I think everything was better 30 years ago and all you kids these days should get off my lawn. Like everything else, there are cycles and sometimes things swing too far, or more often, people pick up the terminology / trappings of a new idea and then ignore the details.
Agile can be like that. Pair/mob programming. Just in time design. Customer feedback. Short cycles. On the surface, or blindly applied it makes no sense. Two people working on the same line of code is half the efficiency. Just in time design turns into no design. We can't ask customers what they want. They just want a better buggy whip. And how can you get anything done in two weeks? It takes two weeks for us to agree on who's doing something, let alone get it done.
But really, these new ideas aren't about how. They're about why, and the how is the means to an end. Pair programming isn't about efficiency. It's about a broader perspective, making sure things are clear and understandable, knowledge sharing, and up-leveling a team. Just in time design isn't "Make a choice then correct it later by fixing the mistakes" it's "Make the informed decisions you need when you need them and know enough".
Customer feedback is really customer involvement. You need to understand what they're doing, speak their language, and understand their pain so you can collaborate on a solution. And short cycles is part of that. It's ongoing collaboration to iterate on a good solution instead of providing the wrong solution later. It's about providing value sooner so in the ling term everyone is better off.
And that's the big take-away/conflict. The focus on the short term requires a long-term view. You need to make the right choice at the moment that balances what you're doing today with what you're going to be doing the next day/week/year.