A few notes:
I can't speak about the Voigt situation. I can say that one of the greatest opera performances I ever attended was Jane Eaglen and Ben Heppner in Tristan und Isolde at the Metropolitan Opera (with the much slimmer but also remarkable Rene Papp as well).
And don’t forget Michelle DeYoung who, as Brangane might have stolen the show in lesser company. I saw that production in Chicago. It had a terrific look, sound and dramatic impact. Eaglen is huge which was not news to anyone who were clamoring for tickets throughout the entire run at the Lyric. An important part of successfully singing Wagner is stamina, as true of Isolde as anything Wagner wrote. When Eaglen floated the first few notes of “Mild und liese”, at the very end of “Tristan and Isolde” and then rode over the orchestra in the Irish princess’ love/death, it was an astounding moment.
Out of curiousity, why is it that male opera singers can be as huge as they want, and still be hired in the "Prince" roles...yet women are fired for the same thing.
Lauritz Melchior is considered by many to the greatest Wagnerian tenor of the last century if not of all time. A critic once said that in his costume for Siegrfried he resembled and was as mobile as an overstuffed sofa.
There often wasn’t much to do onstage in Wagner operas besides signing and standing around—the term “Park and Bark” summed it up well. Which worked quite well in that Golden Age. Of course in 50 years the beginning of this century will be looked upon with nostalgia as its own age of gold, which the then current performers can’t begin to approach.
Callas' vocal difficulties may have been exacerbated by too much weight loss, but her problems lay deeper than that. I have tapes of her early in her career, and even then there were these sudden mysterious lapses
Among opera fanatics this is generally where the gloves are dropped and the fighting commences. Actually any mention of Callas, pro or con, will have that affect. Like dirac I have a shelf full of Callas tapes and CD transfers—“Lucia” from Mexico City in 1952, Act II of “Parsifal” (in Italian) from Rome in 1950, the RAI broadcasts, etc. (Doesn't everyone? ) Whatever the reason Callas had a white-hot career of 11 or 12 years, from 1948 to 1959 or 1960. Her too rapid weight loss came in the middle of that period. She still had some great evenings on stage in the 1960s but they become more the exception.
Where are such voices today? At the "fat farm" being demolished...
Or in graduate schools of music. There are a lot vocal artists in their late 20s and early 30s who can sight read any score that exists and probably transcribe it for percussion and massed zithers but who also have almost no performing experience.
Many of the roads to an opera career no longer exist. Formerly it was typical for young American singers to work in the small opera houses in Germany, for example. Once travel between Eastern Europe and the former Soviet Union to what was West Germany was no longer an issue, these roles were taken by singers from the East. Now they stay in school instead of learning several new roles, understudying some and performing other (smaller) ones. Not the same thing at all.