Why are browser native multi select controls the way they are and do they offer an advantage?

I generally prefer to use native browser controls whenever possible, such as using <input type="date"> instead of some complicated JS date widget. In most cases, I think the user experience is better. For example, in the case of date, most modern browsers provide a date picker appropriate to the platform.

The one gross exception is <select multiple>. They are generally ugly and take up a bunch of space. Their functionality also seems relatively unchanged since their initial conception. To some users, they are not intuitive either (for example, to a user that doesn't know you need to hold Ctrl to select multiple items)

Yuck

My question is two parts:

  1. Why do most browser native multi-selects still look and function circa AOL keyword 1998? Is there a good reason they haven't really changed?
  2. Is there a strong argument for still using the native control over some more complex text input + JS solution (or using a third-party control like Select2 or Chosen)?