They, along with three other people, beat Kaguya. There's no denying that without help, the two would have lost. Assuming she couldn't separate the two, they'd have a chance, but it's debatable. It's impossible to deem whether they could beat Madara together because we don't know the full extend of his powers, such as having a stronger Susano'o and Rinnegan techniques, Limbo shadows being able to use Susano'o, and having the same RinneSharingan techniques as Kaguya or even different ones for that matter.
We've already been showcased how Naruto and Sasuke have gotten much stronger with age, especially with Naruto gaining the other half of Kurama and assuming that he can unite the Tailed Beasts' chakra without physically meeting them. There's also different ways of defeating Madara without the yin and yang seals, though they would be harder to accomplish.