I think the issue at hand for "Dated interfaces" is they do not look like smartphone displays. ergo anyone who has used nothing but a mobile phone, and getting onto a desktop for the first time is an unfamiliar and non-intuitive experience.
But I suppose that's the difference between a system designed for consumption, and a system designed for creating. Let's run down the core differences;
Consumption
The device is locked down, so you cannot modify system software too much.
The device has intermediary layers between the end-user and user's device.
Interfaces and apps can be vaguely customized, but application options can be limited.
Creation
The device can accept any operating system a user pleases to install.
The device can have intermediary layers, per-app, but are optional.
Interfaces and FOSS apps can be customized to a user's will, with expertise and knowledge.
Passively sitting in front of a display and just pushing buttons are key signs of a device or interface made for consumption. A conventional desktop, or at least, a traditional desktop requires more engagement by the end-user. They need to take an active role in how the desktop functions to aid in creation of new media and material.
On a touch-based interface, options for engagement are limited. Sure, you can still create with it, and you can create on an interface originally designed for consumption. But there is no doubt a traditional desktop, once learned by the end-user can allow them to perform the same exact tasks which aid in creation better and faster, with richer tools which possess more information density.
Interfaces like GNOME Shell and Canonical's original response to it; Unity were made more for consumption, because they are highly touch-based with a vast majority of interface decisions made for you. MATE doesn't force you into that, which is why I think a lot of newer people have difficulty using it, and a lot of older people love it so.
Hindsight edit: The above may seems like I am decrying interfaces and devices made for consumption first. Trust me when I say I am not. But I do criticize a generation which prefers to consume more than it creates, as consumption, the act of taking in without returning anything of value or finding value only in a single instance of a work is a part of creation, however if there is less creation taking place, then there is little to nothing of value for many.