A rise in the price of oil over a period of time can be greater than the loss due to contango over that time.
The problem is that if the price of oil just holds for some time then the fund will have a loss for that time due to the contango premium that winds down with time.
However, the USO fund is currently 30% July contract, 15% August contract, 15% September contract, 15% October contract, 15% December contract, and 10% June 2021 contract. (Now the July contract, for example, expires in June.)
And consider a bull-spread. A long-term futures contract is sold while a short-term futures contract is bought. If the price of oil just holds then there is a gain on the long-term contract from contango while the short-term contract has no loss except for contango. Also, a bull-spread is expected to be profitable from rising oil prices because the short-term contract should have more gain than the long-term contract has loss.
To currently use the USO fund as the short-term portion of a bull-spread would require a simple calculation to weight its current holdings.
Well, a few minutes ago the USO fund calculated as holding oil at 25.96 a barrel which is closest to the September contract. Then the UCO and SCO funds, as holding the September contract, are holding oil at 26.23 a barrel. And the DBO fund, as holding the March 2021 contract, is holding oil at 31.52 .