Re. whether or not frame-by-frame animation can be considered deprecated: I think that that depends on the situation.
I suppose it is not unlike other fields where certain tasks have been automated: it opens up new possibilities, but there are also disadvantages. After all, a computer or a machine isn’t a person. While it may work faster, possibly bringing things within reach that were previously impossible, the result of automated processes can also more be more uniform and impersonal. In that sense you can expect that there will always be demand for handiwork because of its unique character, even if it is on a smaller scale as before.
On another note, it is not necessarily so that computer animation is faster to realise as the handmade variety. While it is certainly so that the tweening is taken over by the computer, it cannot do its job without you telling it exactly how. A human animator knows how a limb moves, but a computer doesn’t: so you need to tell it that by way of rigging your character. In one book about Blender the writer even suggests that the net investment is oftentimes not all that different; it’s just that on a computer, you have to put a lot of effort in preparing your scene while the actual rendering is a matter of pressing a button - but in hand animation the major part of the work is the actual ‘rendering’ (drawing).
Wallace & Gromit is a great example of frame-by-frame animation apparently still being economically viable and delivering breathtaking results. Computer techniques were used in some scenes (like the floating rabbits in the Curse of the Were Rabbit), but for the rest it’s frame-by-frame handiwork.
I also love classic 2D animation - most notably, everything from before the mid-1950’s; and I certainly prefer it over a lot of the modern mass-produced animated entertainment. But to be honest, I neither care much about most of the limited animation stuff produced from the 1960’s on - even if that was done by hand. Just compare a Tom & Jerry cartoon from the 1940’s to one made in the 1960’s.
And reversely, there are also absolutely brilliant computer animations being made recently. I suspect that these productions are almost as labour intensive as the classic Disney hand-drawn feature films like Snow-white.
In the end, I think it is the dedication and talent of those involved that produces great results, and that the technology used is far less important. Norman McLaren could create masterpieces without even a camera, but just using film stock, ink, razorblades and pins; Disney and Hanna-Barbera employed dozens of artists drawing by hand, cells, paint and a multiplane camera; Nick Park and Lubomír Beneš a table-top, plasticine, a camera and lots of patience; and Pixar uses a small army of all sorts of creative and technical people and high-tech machinery. They all produced breathtaking things.
But one can also produce immensely boring TV fodder using all those techniques. So I think that that’s a more important factor