It is unlikely for tablets to replace netbooks, but we are seeing lesser netbooks on offer.
When I found that China made Android tablets with 1024x800 7" display, 1GB RAM, 8GB storage, are selling at S$225 at Sim Lim Square, I was very excited about that. The price point is a very important factor.
With that price point, I would get one and explore how useful is Android tablet. To use it for casual note taking, writing short memo, reading ebooks, carrying it around as it is less than 400g.
It can be used by students who can't effort a computer to do simple things like searching for information on the web, note taking, reading ebooks and other learning purposes.
With this price point, it is much cheaper than the first netbook ASUS EEEPC with 7" display and 4GB of storage, 512MB RAM which cost S$699 many years ago. If you prefer to use a keyboard on the tablets, you can always attach a normal USB keyboard to it at home to type a full speed.
I still prefer to have a light weight netbook to do most of my things if there isn't cheap tablets available. But with cheap tablets at that price point, I would start to use tablets for non-series things.