As a restaurant point of sale developer myself (Ambur, an iOS app), one thing: OpenTable isn't a POS, it's a reservation system. I didn't see the conflation between sites and POS systems in the article, but I see it throughout your comment.
Everything else rings true. We have to invest a lot of time into each prospect because they're used to buggy systems that have feature overload and as a result are hard to use and impossible to setup. We're selling at a ridiculously low price ($999 for unlimited device licensing as a single site), and we're doing well, but the time investment into each prospect is very high.
My limited understanding is that some (many, now?) POS systems integrate with reservation systems, but only one at a time, meaning if it's tied with opentable, it's not able to accept reservations from any other service.
It's been over a year since I was looking at POS systems, but that's what I remembered (might be bad memory tho!)
Everything else rings true. We have to invest a lot of time into each prospect because they're used to buggy systems that have feature overload and as a result are hard to use and impossible to setup. We're selling at a ridiculously low price ($999 for unlimited device licensing as a single site), and we're doing well, but the time investment into each prospect is very high.