How would that work? Please explain how to fit 3 massive games on a single cart.
It's 2020. Digital is the future, carts/discs are already "beta" when they release and require patches and updates anyway. You rarely get the "full Game" on a cart.
It's 2020. Physical media is dying at a massive pace, especially with GameStop likely shutting their doors this years. They have no need to use bigger, more expensive carts when the majority of people don't care.
Oh, bullshit. There's a lot of people worldwide that still cares about having physical media with games, even in 2020 in which most of the world doesn't have perfect internet with data caps or people who live in rural areas.
They can easily use a 32 GB card like Square-Enix did with Dragon Quest Builders 1 + 2, what CD Projekt Red Studio had with The Witcher 3: Wild Hunt Complete Edition & what Bandai Namco did with Tales of Vesperia: Definitive Edition.
There should be absolutely no excuse as to why they can't do so from three very old games. They just don't want to because of greed.