I have no idea, though, if the practice of keeping the NFC readers turned off is the merchants' own decision or if they are simply obeying an order from their payment provider or bank not to accept any contactless payment just yet. Banks in Mexico usually own the terminals and payment systems they supply, so they tend to dictate which forms of payment are to be accepted by their affiliated merchants and which not.
In the US, I think in the case of places like Walmart, Kroger, Home Depot, and until recently Target, the decision was entirely on the merchants. While some places have turned it off to work out bugs or there may be a payment processor decision involved, it seems 9 times out of 10 that it's a merchant being stubborn to push some sort of other product/service. For many of the PIN-pad-style devices that I've seen, everything is generally ready to go out of the box (we've had First Data and Verifone units and processing done through Bank of America and Chase).
I'm wondering if in your experience, the magstripe reader is disabled entirely and as a byproduct, contactless via magstripe emulation also is broken? We've had a lot of instances where some places that newly rolled out contactless will have snags - 3 or the 4 card networks will work fine, but the other will say "insert card" even if you do a contactless read, or just not even act like the card is there (I had this happen with Discover in the past - switch to another card and it immediately reads).
I've heard from a few people about how in other countries, the terminals are mostly owned by the banks - I wonder how that would've changed the process here, since many seem pro-contactless.