Your head of product watches a polished vendor demo that stitches together three workflows in twenty minutes. The room nods at the clean UI and promised connectors. Six weeks later the same team discovers the connectors only handle synthetic data and the UI breaks on their actual schema.
Build-versus-buy calls collapse when the decision rests on feature checklists rather than a working slice. The buy side looks cheaper until the integration layer demands custom adapters that the vendor treats as professional services. The build side looks slower until the team realises they already own half the required plumbing.
Strategy decks hide the hand-off points that always create the real cost. A deck can declare “single source of truth” without naming which system will lose authority when two records conflict. A shipped prototype forces the argument into the open because the conflict appears on screen within the first test load.
Australian SaaS teams still measure progress by the number of approved roadmaps instead of artefacts that reach customers. The product manager who insists on a live endpoint with real authentication and one customer dataset before any further planning cuts the fantasy cycle short.
Craft shows up in the error handling, not the happy path. A demo that never triggers a duplicate record, a timezone mismatch or a partial API failure tells you nothing about the engineering quality that will determine support load after launch.
The fix is simple and uncomfortable. Require every major product decision to survive a two-week slice that accepts live traffic from at least one real account. Anything that cannot survive that gate stays on the deck and out of the release plan.
Teams that adopt this rule stop celebrating completed decks. They start tracking how many proposed features die once the first real user hits the edge cases the slides never mentioned.