I wouldn't say that merchants are going to be left out, I mean we have to understand where they are coming from. First, bitcoin is very volatile assets, if merchants are just relying on this businesses to make money, then it make sense that they won't accept bitcoin as payment. Second, if merchants wants to accept it as payment system, but if they are not technically inclined, then they might have difficulty accepting it. And with that as business owners, maybe they will have a hard time to really put the logo of "Bitcoin is accepted here" in their stores.
they will find their way how to adopt this payment system later on if they will see the benefits it will bring to their business. as you said, for now, they are still hesitant because of the volatility factor, where a lot of merchants are not yet ready because they are relying on their day to day income. but they will come around once the adoption is much stronger among their customers and find their strategy on how to take advantage of this volatility aspect of crypto.