We don't know that they had a choice. If you've signed a contract, with penalties, for 15 launches, you might know you're doomed but have to press on anyway. The Eurofighter is another example of this - when the UK govt tried to cancel its Tranche 3 order, it found the penalties would have been more than the cost of the aircraft...
Launching satellites etc are expensive and time consuming. Agreed. But even when Iridium launched it's satellites were not fully operational. They would have probably had enough warning to iterate on a different product