Only if everybody uses phones with Apple Pay compatible payment systems will every business see the need to support Apple Pay. I hope everyone gets on the same standard soon.
Additionally this system offers a secure mechanism to the merchant as well without making a dent to their business processes. That should motivate them to move quickly on it to prevent Target/Home depot style mess.
Finally the narrative around this is going to evolve the public perception. They are going to demand this from merchants for security, which should move the ball forward.
The merchant may end up facing higher fees for using card & sign terminals instead of chip & pin or NFC & token.