Most 7on/7off night jobs are not filling and falling by the wayside. Like others have mentioned 7on/14off is becoming the new norm. Some 2nd shift jobs (ie. ~5pm-1am) are still 7on/7off but are more sustainable long term.
Very few people want these jobs, so they will always be available. Even in the last bad job market 5-10 years ago, these jobs were available.
Most require you to be on-site, some you can live anywhere. Most are salaried, some allow a path to partnership. Most are on the higher volume side compared to day work.