I agree, traditional animation was better than modern CGI, but I don't think it's as simple as CGI being an inherently worse medium, but that films are produced more cheaply. Some weeks ago a friend and I were watching and comparing some scenes of Snow White and Cinderella in English and Spanish and were stunned by the singers in both languages. How often do you hear actual opera singers in modern Disney films?

So, yes, what you say may definitely happen, but it's a trend some graphical industries have been on for decades. It's why there are so many fewer professional animators anymore. I wouldn't be surprised if some techniques of traditional animation have been lost by now.