Tons of people. There's all the people using old computers, because they're still plenty good (except when using applications written by people who think they don't have to worry about memory), and all the people on shoestring budgets using cheap computers that are for the most part good enough (except when using applications written by people who think they don't have to worry about memory).

Also, people who let their machine and browser rund 24/7. I'm currently stuck with an 8GB machine because I hit the maximum RAM supported by the mainboard and I don't have the time to go through a full productive machine migration right now.

So I restart my browser every 48 to 72 hours to reduce the memory footprint (which is one of those clunky "hacks", but it still works).

If you think everyone or even most people out there want to upgrade their computers every couple years, and go for models with lots of RAM in them.. I'm sorry, you're wrong. Some geeks might have 16G or 32G but that's it.

Besides, whatever happened to Web browsing being a lightweight activity accessible for everyone even on his grandma's old PC?

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.

And who would want to use a browser anywhere other than a PC, right?

We appear to be talking about ABP on desktop firefox, no?

It's true; my comment wasn't fair.

Returning to your original point: I've been working on Firefox's memory consumption for about three years now. There are quite a few people who take your viewpoint. But there are also plenty of people who care very deeply about memory usage. Some of this makes sense, e.g. from people who are on low-end machines. But some of it is less rational... there is a subset of people for which memory consumption is almost a moral issue, and excessive usage indicates the general decay of western civilization, or something like that.

The problem surely applies just as well to ABP on mobile Firefox?

> In a browser-on-pc setting, who even cares about memory any more?

I do. I have 16GB of RAM (the max for my computer) and have 3GB of swap used. About 8GB of that is Firefox, and I (obviously) run more than just a browser on my computer.