On the other hand, getting a big company their own TLD can be easier to maintain. For VW, having everything under the .volkswagen TLD means they don't need to have 100 different domains for each country (like volkswagen.com, volkswagen.co.uk, volkswagen.fr, and so on), each of them with different terms (in some countries you have to pay a yearly fee, in others you don't).
On the other hand, the new TLD only means just another name to maintain, as I don't think anyone will actually remove the ".com" domain when they get their own TLD. One of them will be redirected to the other, and for 99% of the time the custom one will be redirected to the older.
But wouldn't Volkswagen still want to maintain all of those domains? I highly doubt they're going to give those all up for either competitors or domain squatters to snatch up.
So really in the end, a custom TLD is just /more/ money they need to shell out for protecting their name online.
On the other hand, the new TLD only means just another name to maintain, as I don't think anyone will actually remove the ".com" domain when they get their own TLD. One of them will be redirected to the other, and for 99% of the time the custom one will be redirected to the older.