Yep. I've been through this cycle too. The phrase that helped me sell the idea was "estimation is design". You can't come to an estimate that has any relationship to reality without knowing what you're intending to build, and that's a design function, even if it's very high-level, coarse, and approximate. Just expecting that design to materialise from thin air is extremely unrealistic, so you have to go through some sort of intentional process to get there. Making that process cause an appropriate amount of pain does make it clear that none of it is free.