Since you're able to use ones from past chargers I'm guessing they expect a lot of people to just re-use the one they already have if they need the extra length... one less thing that may end up in the trash bin.Yes - the one Apple used to include for free until they realised it was a sales opportunity...
I'm assuming you're working with a new 15" MBP? There are other charging cables on the market that will pass up to 100W as evidenced by some excellent research here, a link posted by someone in another thread:
I have since found a new monoprice option that is cheaper than the two listed here but it maxes out at 3ft. Basically, there are no cables right now that are able to pass up to 100W that are longer than Apple's charge cable, so that continues to be your best bet until there is.
update to this thread: Benson Leung (who's the google guy who verifies USB cables according to spec and keeps them in the spreadsheet) reviewed the AmazonBasics charging cable
He recommends the 9ft version for charging.
I don't see this cable being recommended on the google sheet? am I missing something? - Also I am not sure if these specs would be enough for 100w? "power output up to 5V, 3 Amp"
That's how I read the specs too. Where's the 100W specification? Does it test that way and is not documented?