I was just reading about this. Seems like changing a payment system anytime close to Black Friday and the Holiday shopping time is risky. It's a matter of days yes, but why not do the change earlier in a slower month like October?
G does not offer a replacement processing solution for physical goods and services. They did partner with Braintree, Shopify, and Freshbooks; neither of these are ideal as they all still require a transition, but at least Google apparently has negotiated discounted migration options for its Checkout users.
I'm wondering if wepay would be a better option here.