It's not about "multiple separate wallets", it's about having the choice of provider. Choose one and stick with it. I assure you Apple Pay will be fine.
Once again, people are not seeing the bigger picture.
Apple Pay is supported by so many banks precisely because it's the default choice on iOS, and banks know that it's either get on board on risk fewer people using their credit card services in favour of a competing alternative which does support Apple Pay.
If there is choice, there is a higher chance that banks may simply elect to not support Apple Pay in favour of pushing their own mobile payment alternative. The end result may indeed be more choice, yes, but fewer meaningful choices because the person electing to use Apple Pay will find that fewer banks support it and it can only be used in fewer places.
This is the whole point of Apple not giving users a choice in certain areas. By putting their weight behind a single option, Apple is able to use its influence to negotiate for better benefits for the end users. Would developers have agreed to incorporate ATT into their apps (better privacy for us) were the iOS App Store not the only option in town and there were alternative app stores available?
So I don't really care about more or less choice; I care about what that means for me, the end user. As it stands, I am already able to use my choice of credit card for Apple Pay, and I am in favour of Apple Pay continuing to be the sole option on iOS so that
1) All banks are forced to get behind said technology
2) More businesses are forced to support it so I can make payments with it
More options will only dilute the bargaining power that Apple has, to my detriment ultimately.