I don't believe there are not artists today who could animate deer antlers or paint beautiful backgrounds. Disney did not want to pay for them or wait for the time it would take to animate a film by hand.
Bambi lost $200k USD (as a result of being released during WW2) in 1942 when it released[0], the equivalent of ~$3.4 Million USD today, so I'm sure they were cutting necessary costs. It only recouped the losses with subsequent re-releases, which had the benefit of access to the European market.
0: https://en.wikipedia.org/wiki/Walt_Disney#:~:text=The%20mili...