This data was iffy then — not really enough data points, and the trendline is dubious:

Source: a very timely xkcd

That said, the company DxOMark does measurements of camera sensors all the time, designed to be resolution-neutral. Here's a chart of the "Sports" score, which is based on SNR, from all tested APS-C camera models from 2002 to 2018:

Given the cartoon above, I won't try to draw a line, but

1. It's pretty clear that there's a slight upward trend
2. That trend might not have been obvious in 2008, but it seems like it's probably actually also there.

If you look at overall scores for the same cameras, which include dynamic range and color depth, you'll see the same general sort of upward trend, although it's arguable that there's more growth to around 2010 after which it kind of levels off.

In practice:

1. All cameras over the last decade do very well on these measurements.
2. More megapixels don't seem to be hurting.
3. There are cameras within any given year's cohort which would fit right in ten years later or ten years earlier. That is, waiting until next year is unlikely to give you a see-in-the-dark miracle.
4. Don't worry too much about this. All of the cameras produce excellent results even in very, very little light.
5. None of these measurements really matter to making good photographs.