I read a book on Tin Pan Alley this year, and the author spent a while explaining how Sinatra loved Heifetz's phrasing (lots of notes per bow) and tried to emulate it in his singing, so he owned every recording Heifetz ever made. Yeah, I got enthused and clicked some value-for-money things on Amazon and ended up with a 4-disc boxset of Heifetz playing concerti and a 9 disc box set of him playing Beethoven. Err, yeah, I haven't listened to much of that one yet! 9 discs is overkill.
Normally I don't compare artists - I just want music on in the background, so I find an artist I like and stick with them. But Beethoven's Spring Sonata is interesting - Menuhin (afaicr) seems to play it very slowly, and Heifetz (afaicr) plays it at twice M's speed (slight exaggeration)! I think I'll aim for somewhere between the two when I start on it next summer. (I wrote the two speeds down on my sheet music. When I can find it, I'll put them here)
I always thought that classical was only played at the same tempo very strictly. I didn’t think it had the freedom as other genres.
Originally there was just andante or allegro or whatever, no metronome markings. Modern metronome markings are just one editor's suggestion.
As it happens, the Spring sonata starts allegro, and all that means is merry or bright, and that isn't strict in intention, just a mood setter.
Menuhin plays crotchet (quarter note) = 116 (which I find too ponderous); Heifetz plays crotchet = 138, which may be right, but it would be too fast for me to achieve for a while, lol!
On the topic of classical tempo markings: one of my conductors has opined several times that a tempo marking is a mood, not a speed.
If you think about classical music in general, it can't possibly be that strict because we've only had recording technology for about a hundred years and the language of printed music is not very precise for anything other than notes and rhythms. For most of music history, composers wouldn't have been able to give performers anything to follow strictly.
By the way, one of my most interesting performing experiences was about a year ago, when both of my orchestras were playing Beethoven's 8th at about the same time -- they performed just two weeks apart, in almost diametrically opposite interpretations. For the four weeks that rehearsal schedules overlapped, I was going back and forth between one orchestra that played at the fast end of the spectrum of recorded tempos (e.g. half note = 74 in the last movement) and one that played at the slow end of the spectrum (half note = 62 in the last movement). Bowings and articulations, and even the amounts and types of vibrato the conductors wanted, were different too.