What does Isaiah 5:10 mean?

Here the prophet reveals one reason the great houses of the rich will sit empty with nobody to enjoy them (Isaiah 5:9). The farm-based economy will take a nosedive. Years of drought or blight will reduce crop yields to the point where a ten-acre vineyard only produces one bath of wine. This measure was equivalent to about eight gallons or thirty liters. Likewise, a homer of grain seed, about eight bushels, will only yield one ephah, about one-half of a bushel.

Those terrible returns on investment are so bad that wealthy landowners will be forced to downsize. They will be driven out of their sizable homes to occupy smaller ones on less land. In the end, their greed was futile. Instead of building their fortunes, they over-extended and lost much or all their wealth.