It hasn't changed, and I don't know why people are saying that most books don't have DRM. It is only a small minority.

Tor books is the largest publisher without it (owned by Macmillan). Otherwise everything is truly hard DRM either ACSM with epub or Kindle's. They are both more or less easily defeated though.

Because these are people that don’t buy the books anyway. They pirate them and put them onto their 2010 Chinese ebook reader.

Kobo does carry DRM-free books, and I've never encountered DRM on any books I bought directly from authors' or publishers' websites either.

The vast majority of kobo books are still ACSM protected.

There is a difference between hard and soft DRM. Soft DRM can be only some watermark, not keeping you from creating copies for your own devices. Hard DRM aims to prevent any copying.

In my experience soft DRM is very common, hard DRM not so much.