The Grand Theft Auto series has always been famous for using within its gaming world its brands that mimic the brands you have in real life and also if this feature is part of the identity of the series, there would be nothing wrong with having cars licensed.
Among other things, it is no wonder that the mods that introduce real machines have always been among the most popular in the series.
Grand Theft Auto is one of the most profitable series ever and Rockstar Games obviously has the capital necessary to invest in car brand licensing.
It would be great in Grand Theft Auto VI to drive a Lamborghini or a Ferrari instead of Hell. Real car brands would also help make the gaming world more credible.