“The future is already here, it's just not evenly distributed” © William Gibson.
It already works this way on modern Windows: WPF, UWP, and Direct2D already use GPUs.
> it is hard to imagine that we will be directly working with triangles
Most people doing 2D graphics on CPU don’t moveto/lineto either, they use higher-level libraries for that. To be good at it, you have to understand, to some extent, couple underlying abstraction layers. That’s why universities are teaching these basics. The basics for GPU-rendered 2D graphics are totally different, and until very recently only 3D graphics professionals cared about them.
> either 3D should go continuous (e.g. implicit surfaces)
You don’t necessarily need implicit surfaces. If you have a GPU ≤ 10 years old, you can convert 2D vector stuff to triangles on the fly.
Here’s a simple example that renders a polyline: https://github.com/Const-me/vis_avs_dx/blob/master/avs_dx/Dx... It cuts a few corners e.g. doesn’t handle self-intersecting polylines particularly well if you have transparency, but it’s all fixable, that was an unpaid hobby project.
Often you can do the same with Bezier/Nurbs, see tessellation stages in D3D11 docs.