Is "score" a Bible of Interpretation?

Since I went all out yesterday with French pop "grandma's music", making my French husband and in-laws quite alarmed :)  Today I go back to classics.    Like anyone, I like comparing performers, listening to different violinists playing the same pieces; or at least I used to, comparing old timers.  Today not so much, as younger generation of violinists seem to be not too distinguishable from one another, and I don't find it fun.   Just because my daughter is playing the extraction of "La Donna E Mobile" from Rigoletto for her piano lessons, here I go.

As I mentioned yesterday, I really like listening to singers of any genre, and get a lot of performance ideas in terms of phrasing.  My old violin teachers also used to say, "listen to the singers!".  I'm not an opera specialist but my interest is very specific in today's case: rubato of a part of a phrase.  Here is the text of the first 16 measures of the song.  I'm specifically listening to the underlined italic places:

La donna è mobile

Qual piuma al vento,

Muta d'accento — e di pensiero.

Sempre un amabile,

Leggiadro viso,

In pianto o in riso, — è menzognero.

(Woman is flighty
Like a feather in the wind,
She changes her voice — and her mind.
Always sweet,
Pretty face,
In tears or in laughter, — she is always lying.)

Call me old fashioned (I really am, despite all the "revolutionary" Subharmonics and interactive computer systems  :)    but my favorite is hands down, the good old Mr. Enrico Caruso.   And here is the reason.   At the underlined second-half of the phrase, he is practically the only one I could find, who does "rubato" to the degree that's almost distorted in terms of tempo.  He takes quite a liberty in making a very noticeable ritardando (slowing down).  He does it every time,  making very clear contrast, as the text corresponds in contrasting character.   Even if you don't understand the Italian lyrics, you know something is different because of the way he sings.

So I was curious, as I can't really find anyone sing the way Caruso does, I went on Youtube doing a "La Donna E Mobile Sing-Out"  :)  The quality of these recordings isn't the issue; you are just listening to how these tenors sing the first 16 measures.  I found it curious that after Caruso, the singers of the following generation sings with more and more rigid tempo-- almost no inflections at all.   Really, nobody sang like Caruso after him.  I do enjoy all of them in a different way, but again, I'm just interested in this specific item.  If you like, click on the names and compare yourself:

1. Here is my "winner" Enrico Caruso. (b. 1873)
2. Mario Lanza (b. 1921) slight "tenuto" where Caruso slows down
3. Richard Tucker doesn't quite slow down as much as Caruso but clearly sings with contrast
3.5 (new) Alfredo Kraus does almost slow down once
The "Three Tenors" sing it with no tempo change at all.

4. José Carreras, and his earlier version which I prefer (less audio quality)

5. Placido Domingo  slowest, no rubato except for the fermata at the end of the verses like everyone

6. Pavalotti sheer power house, I don't have much else to say...

Now, the younger generation, theirs maybe slightly more in variety and freedom than the previous generations of giants.
7. Rolando Villazon pretty much following the previous generation
8. Marcelo Alvarez see above, even more straight than Villazon
9. Jonas Kauffman no real rubato, but certainly a lot freer than the "3 tenors" from the last generation (at the end you can see Carreras is in the audience)
10. Juan Diego Florez does the slight ritardando a few times a la Caruso

I wrote yesterday, that without the recording of old works while the composers were alive, even with today's scholarly performance practice studies, we maybe performing a very different music from what was originally intended.   Caruso is the closest to Verdi's generation obviously, born 20 some years after Rigoletto was first performed in 1851.  He sang Rigoletto making his debut two years after Verdi died in 1901.   It is very possible he heard Rigoletto while Verdi was alive, and it maybe that the singers of that time sang the way Caruso does.  Or, this "slowing down" was Caruso's unique way, that he made the mark on his own.

More "composer-centric", or clearer the interpreter/composer division became in the 20th century, the "liberty" such as of Caruso's, seemed to have become shunned or frowned upon.  "It is NOT WRITTEN!" to slow down, so you don't slow down like that.   We have become more faithful to the score, taking it as the "bible" of interpretation.  It seemed to have made us sacrifice the freedom of individual expression and we have achieved the conformity instead.  Is it too cynical the way I put it?  :)