(First of all, I hope this doesn't sound like a loaded question. I do mean it sincerely.) Do you know why thinner ballerinas are preferred nowadays? I've been looking at photos of Vaganova when she was teaching, and her students didn't look as lean as the current students at the academy. It seems strange to me, because Agrippina Vaganova's standards seem to be otherwise worshipped.
I think it’s a great question! I have a theory on why the standards have changed so much but, as always, I welcome other input. Here’s what I think happened:
Beauty standards have changed
What we consider beautiful has changed a great deal in the past 100 years. At the turn of the 19th century, when consumption was laying waste to the European population, thinness was associated with sickness. It was an undesirable trait, and women were often criticised for it. For example, the great Sarah Bernhardt was the target of many terrible insults because she was slim.
If I’m not mistaken, Anna Pavlova almost wasn’t accepted into the Imperial Theatre School (now Vaganova Ballet Academy) because she was very skinny. You can see how different she looks compared to her classmates in this photo (taken in the 1890s):
The ballet of the olden days favoured a more sturdy (and therefore, healthy) physique. Whereas now we find long, thin limbs, high arches, flat torsos more aesthetically pleasing. Think of the way your eye glides over Svetlana Zakharova’s body.
Genetics have changed
Humans as a species are in an evolutionary fast-lane. This means that we’re changing at an incredible pace. Even now, whenever Tsiskaridze recalls what ballet kids looked like (physically) in his day compared to what they’re like now, the difference is staggering. And the generations he’s comparing are only 30-ish years apart! By the way, according to Nikolai, the health of Russian children is rapidly deteriorating from generation to generation. I’m going to do a separate post about it later.
Ballet itself has changed
As you said, the standards set by Agrippina Vaganova are still very highly regarded. However, some elements of her teaching have been (and continue to be) discarded because they have become obsolete. For instance, according to Vaganova, the ballerina mustn’t raise her leg above 45 degrees. Clearly, no one’s going to follow that rule anymore. Both the technique and the overall aesthetic have become more… streamlined, I guess.
Additionally, men have a much harder job now than they had one hundred years ago. Partnering has become a lot trickier. The lifts are more difficult and there are far more of them. This means that the ballerina needs to be smaller and slimmer, otherwise the feat becomes physically impossible.