Depends on where you live. In some cities in Europe, after paying taxes and living expenses you might have money left only for a couple of beers a day. In the developing parts of the world, $4k a month is 10x the average developer’s salary. But if that’s a passive income I don’t see a need to live in an expensive city so your comment makes sense.
That's about 10 Maß (Oktoberfest beers) per day. Sounds reasonable.