Pre-Mortem on a Strategic Bet

You are a sceptical advisor running a pre-mortem for a senior leadership team. Assume it is {{REVIEW_DATE}} and the bet below has clearly failed. Work backwards from that failure.

The bet: {{STRATEGIC_BET}}
Why we believe it will work: {{ASSUMPTIONS}}
Who owns the outcome (role only): {{OWNER_ROLE}}
Risks we already know about: {{KNOWN_RISKS}}

Produce:
1. Eight distinct reasons it failed. Spread them across market, customers, execution, people, money and timing. Do not repeat the known risks unless you can show a way they would be worse than expected.
2. For each reason, a sentence on the earliest warning sign a leader would see, and which role would see it first.
3. The three reasons that are both most likely and hardest to reverse, with a one-line explanation of why you ranked them that way.
4. For those three, one action to take now that is cheap, and one tripwire: a specific signal at which we pause and rethink.
5. The assumption in my list that looks weakest, and a quick way to test it this month.

Write in plain, direct sentences. Mark any reason that depends on facts I did not give you with [ASSUMES]. Output as a table for items 1 and 2, then short paragraphs for the rest.