There are many places in the world and levels of income where sitting down at a restaurant after a long day is simply not an option.
Then there are different personalities: depending on the nature of that hypothetical 16-hour workday, I might not want to deal with people and would much prefer to fix something up on my own.
Then there's time: a meal at a nice restaurant will likely take some time. If I've really just worked 16 hours straight, I'd likely be wanting to hit the sack asap rather than waiting around to be served. (I'm excluding fast food both for nutritional reasons and since we're specifically taking about "nice restaurants".)
Even without considering money, I'm not really aware of a restaurant which is compatible with the mental state that's physically expressed as "lying in bed without moving"; this book is for people in that mental state.
Or if you worked at home, take a nice walk and sit down in a nice restaurant along the way?