I arrived at the same wisdom eg. the "Throw Away then Strategize/Plan" process, but... how the heck to you manage to sell/explain this to people at the same or higher levels?

Imo lots of people are very disgusted by this, mainly because the (a) concervatives/waterfall-heads are horrified by the idea of launching something no thoroughly engineered, while the (b) evolutionary-design folks never want a clean-rewrite from scratch, they'll cling to that "throw-away version" and try to "evolutionarily" refactor it gradually into what they now know it will be needed (and this always fails).