Amazon Basics 100W Four-Port GaN Wall Charger with 2 USB-C (100W, 18W) & 2 USB-A Ports (12W), PD 3.0, Foldable Plug, Portable Multi-Device Charging for Laptops, Tablets & Phones, Non-PPS, White

    You'd think depending on the person, they'd travel with 
    EITHER their phone OR their iPad OR their laptop

I sometimes travel with all three. You're missing a few major scenarios.

- The iPad works as a second monitor for a Mac laptop. Great for creative/tech people.

- If people are traveling for work, they are bringing their work laptop which may have corporate lockdown/spyware software installed. Therefore they may not want to or may not be able to use their work laptop as an entertainment device. (Not to be crass, but: watching porn in a hotel room is a pretty common use case)

This is not an onerous load for a airplane carry-on bag. Although, a smaller person or somebody with an injury or disability might feel differently.

    At least - thanks to the EU - soon they can all share the same USB-C charger.

They already can. Though you still need 2+ cables. https://www.amazon.com/AmazonBasics-Four-Port-Charger-USB-C-...