I'm another person who doesn't see those results as suspect. There are a bunch of reasons for that.

- Some people do most, if not all, of their reading on vacation. For them, an ereader may be an unjustified expense.
- Many people who do read ebooks use their phone or tablet. That will work out in transit, but it won't work out on the beach.
- Light readers won't see much of a benefit to travelling with an ereader. One book is only slightly bulkier than an ereader.
- There are certain points on the flight where you cannot use an ereader. You may disagree with that, but rules are rules.
- Books create less hassle with airport security and customs since they'll be ignored in most cases. Ereaders will probably be ignored, but may not be.
- Certain people are in the habit of reading ebooks while travelling, others are not. As such, a frequent traveller may reach for their ereader while someone who only flies on vacation may only think of a pbook.
- Risk of loss or damage is also a concern. Even a cheap ereader costs as much as two or three newly published novels (and more, if you're happy reading older titles). Since you're moving around there's a risk of loss. Since you're stuffing things into bags, there is a risk of damage.

Oh, and some people just don't know about baggie trick.

I'm sure there are more reasons too.

Personally, I have travelled with my only electronics being an ereader (not even a phone). But I'm unique. I'm sure that a lot of people here are unique too, since most MR participants seem to be heavy readers or technology obsessed.