Isaiah isn't asking us to quit our jobs or to give away our money. Jesus is the one who does that sort of thing. Isaiah simply questions how we view work and money. He wants to know if we care more about what is on sale at WalMart than how the scripture reading for today impacts our lives. Come to God's feast, it is the only thing that will bring true joy.
Monastic life is unique.
When one becomes a monk it is a vocation of prayer. Each day there is laundry to be done, plumbing that needs to be fixed, dinner for 30 people that needs to be cooked, they maintain a web site, have a gift shop, welcome and provide for guests. Running a community of that size is no easy task. There are lots of things that need to be done, but none of them are their job. These are all alongside of their job.