Restaurants might not be lazy in their core business functions, but that doesn't make them non lazy on other matters.
Perhaps a better way to say this is: restaurants are good at being restaurants, but aren't always good at establishing an online presence. A big part of why these delivery services succeed is that they provide a function that restaurants aren't well suited to provide on their own.
This isn't about being lazy, it's about an industry needing to adapt to the new expectations of the app economy, and often not having the expertise to do so.
That's the majority of all businesses. And like many similar industries, the razor thin margins don't allow restaurants to properly invest in tech.
Times change and circumstances change. Businesses either evolve or get replaced.
The problem now is that delivery services are being subsidized by VC money or however Uber is getting new money after their IPO.