Even if they can recover the engine intact how many times can it be reused. Saving a few million on a higher chance of blowing up multi billion payloads is not exactly wise economically.
Think of it this way: if they can fly the first stage 20 times, that along with some cost optimizations of the upper stage could cut the cost per pound by a factor of ten. Then it would become economical to launch mere multi-hundred million dollar payloads. That would dramatically reduce the economical risk of any single launch, as long as the rocket is not ten times as likely to blow up, but rather only maybe twice as likely.
Of course, anyone who launches a lot of rockets of the same type is likely to become really good at getting that type to orbit in one piece. Just look at the Russians and their now ancient Soyuz rocket.
Keep cutting costs and you might one day have a system where you could launch a ten million dollar payload, which you could easily insure at your local insurance company.