Even a chromebook has multiple GB of RAM now. Yes, a lightweight browser on old machines is desirable, but everything has had more than enough RAM for an extra 100MB for ABP for multiple years.
The Chromebook Pixel I'm sitting behind right now has 4GB. I find it frequently insufficient for Chromes needs. I bought it a year ago; the websites that I use give me the same sort of content that they did a year ago.
