There are at least 2 normal increments between 720p and 1080p.

The point being made is that doubling the number of pixels is quite significant. Calling it incremental is a little short-sighted IMO.

I was originally going to note exactly that, but then I actually did the math and noted that 1366x768 is 1.0005 megapixels, and 1920x1080 is 1.98 megapixels, which is pretty close to an integer increment when looked through that lens, so decided that was worth accepting (and interesting enough in a nerdy way to allude to).

Not a hardware guy -- would that be 720i and 1080i?

At least for wide screen ratios, there’s 1366x768 and 1440x900

1280×720 (720p), 1366×768, 1440x900, 1680×1050, 1920×1080 (1080p FHD)