"Modern" is such a silly way to advertise things.

We don't have a marketing department, so we're happy to take suggestions on our messaging!

What makes it modern are the ideas behind it: the column-oriented layout, support for lightweight encodings such as FSST and FastPFOR and support for pre-tessellation. Also, enabling doing more computations on the GPU instead of the CPU, which are made possible thanks to modern graphics APIs like Vulkan and Metal. I agree that it is better to be specific about these things (if that is your gripe with it), but there's only so many characters that fit into a title. ;)

Although the word is overused, hindsight can be a huge advantage in design.

It should be backed up, for sure. Like how is this modern?

In this case it's the column format for attributes and the newer encodings. Things the industry wasn't doing a decade ago.