I'm fairly confident that they understand it better than you or me. The issue is that they have to make it a no-brainer for a large retailer, like Starbucks and Home Depot while not giving away some of the major reasons it's a win for the consumers, such as privacy, ease of use and security. Walgreens' kludgy deployment is an example of letting a launch partner have too much say in the experience. Buying something from Walgreens with Apple Pay is a little like filling out a job application. Contrast that with Whole Foods and Sprouts, who make the whole process easy-peasy.
On top of that Apple needs to show smaller retailers that this is a good thing for them with the new EMV cards coming, because it will save time at the register.
Even at that, Apple Pay has done more to advance contactless payments in about a year than Google Wallet did in the 4+ years it existed prior.
I don't think I agree with you 100%. McDonalds has had Apple Pay since the beginning, are you saying that they are not a large retailer? Or are you saying that it will take longer to train people at other retailer than the time it took at train at McDonalds?
Oct 1st has come and gone, we are all supposed to be on EMV. I don't see why it is so difficult for companies to integrate the new devices. Based on my shopping experience, even at stores that has not had the chance to properly train their employee (but have the system in place already), employee can typically figure out how to work it in about a minute.
As for the smaller business, its even easier. Square (and similar product) offers a simple device for both chip and signature, as well as NFC.
I personally think this is just companies trying to get away with things, because change take time and money. Frankly, if the new rule about credit card fraud wasn't put in place, I bet we will never see EMV, at least never in the US. This is just how most of the American companies are, greedy and slow to react to anything. They like to count the trees, but they never bother to look at the forest.