Right then other things they could do:
- provide some helpful text explaining to users how to switch between years
- use an external library with a custom date picker
The reason why I wouldn't recommend the approach they went with is because there's all sorts of aria-related properties and semantic meaning for screen readers that type="date" carries. This is especially relevant for the target audience they're talking about. I guess the third option is
- what they did but actually try it with a screenreader yourself. Make sure your aria labels make sense and is navigable for both keyboards and screenreaders (two separate issues). Also make sure you're replicating the validation logic that type="date" gives us for free. Basically replicate all the complex HTML5 logic and semantics