Were the duration of the phases shortened? The quote makes it sound like the duration was kept the same, just that the following phase started before the end of the previous phase.
I'm not sure which "quote" you're talking about. I carefully did not say Phase 1 was shortened.
The reason for sequencing, in the abstract, would be that if Phase 2 looks like "hey, this thing really works!" then the pressure to approve it would become irresistible. Whereas if Phase 1 finds unacceptable side effects, then Phase 2 would never start.
Note again that I'm not saying that's what happened.
phase 1 is for safety
phase 2 is for efficacy
phase 3 is for dosage
They're not the same. Shortening Phase 1 is automatically a compromise with safety.