For nearly 10 years I used a compact netbook with an Intel Atom Z530 1.6 GHz and 1G RAM, a Nokia Booklet 3G. I swapped the HDD for an SDD, and given its fanless unibody aluminum design and its 10.1in 1280x720 screen, it was silent and useable for basic office computing and 720p video, with a full-sized HDMI out. Even with Debian I used to get 6 to 7 hours of battery life. I used it extensively for note taking, dabbling in Python, and writing. It was slow, but more reliable and less buggy than running Debian on my older MacBook Pro (which had hardly any battery life left). I used the Nokia Booklet until its motherboard died in 2018, and I still miss that little machine's compact simplicity and utility.
The cheap netbook market just kinda died and got replaced by more expensive "ultrabook" market. I used my Samsung N130 quite a bit, only real thing it missed was serial port but no laptops nowadays have it sadly
I would say netbooks were replaced by phones as first computing devices. Can you learn how to program on a phone? Probably not, not the same way you could on a little netbook.
Most consumers buying netbooks weren't buying them for programming, they were buying them to, as their name implies, surf the net, and that made them the first victims of the mobile device revolution as now you could surf the net much better on a phone or tablet and had better UX and much more addictive apps.
Netbooks being used for programming was a very niche use case (maybe not on HN, but in general). Most programmers had more powerful and versatile PCs/laptops at the time for that.
That explains why they disappeared so quickly. But yeah, they were excellent for cheap linux devices.
I dodged the Atom and picked up an Acer 1810tz. 4gb RAM, intel U4100 CPU, ran rings around netbooks at the time and I still use it here and there to this day. Probably the best keyboard I've ever used on such a small device.
I actually upgrade from the 1.66gz atom to a 1.3ghz ULV core 2 duo, and it was way faster.