The word translated as "fruit" is a play on words. Its primary meaning is "fruit," "seed," or "offspring," but its secondary meaning is economic "returns," specifically, "profit," as we would say "fruit of our labors." In this verse, the first use means "fruits," while the second use, the meaning is clearly "profits" since transporting the grapes seems unlikely, especially since there was a wine vat on the property. Since the word "fruits" also means "produce" generally, it could also mean the wine that was produced.
Notice how this play on words is lost completely in the NIV, which translates "of the fruits" as "harvest." If I were Jesus, using all these clever plays on words, a lot of this Biblical translation would make me sad, but, in Jesus's case, he would probably laugh as his plays on words sail right over these translator's heads.
The economic assumption here is that ownership of land (or means of production, if you want to get all Marxian) deserves to profit from the produce of the land. The fact that the "husbandmen" do all the work does not mean that they should get all the benefits. The owner expects a profit.
Christ's Words in Matthew as a Guide to 40 Days of Prayer.