No one gets paid for low notes unless maybe he is Amonastro or a Russian Bass.
People like high notes. Over the decades the fascination with high notes has grown. Higher and higher. No note is too high. No upper limit. We like to hear that “excitement”. My late colleague and nemesis, Elizabeth Howell, used to call it “bullfight singing”. In some ways, she was correct. The public only knows that the sound is thrilling (like a scream), they don’t know if it is costing the performer to make that sound. Can you scream over and over and over and not hurt your voice? It seems like you can’t but really, no one knows for sure.
Common sense says this is a bad idea but there are famous people who specialize in extreme vocal sounds who do things that would scare most singers to death and they survive, even thrive, doing so. I don’t know how they manage, as it would certainly kill my little silvery soprano, but in my years of dealing with singing, I have seen and heard all kinds of things that would raise the hair on your head and not all of them were easy to explain, but they exist and people do them.
Since I still have an easy high voice, my students usually end up singing higher as they work with me, often quite a bit higher. I teach them to do what I do. Since most of them want to work, having their voice extend into a higher range gives them more options and allows them to get those jobs and be healthy in them. This is part of what they pay for. This is crucial in rock shows, as rock music doesn’t generally consider SATB at all. You just sing and you go up and get loud, and then go up some more, as needed. The “rock scream” is a necessary reality in many styles and, since we have just acknowledged that most humans don’t go around screaming for hours every day, this in itself is a very outside the box vocal behavior.
Most of the youngsters who come in are trained at school to fit into the soprano, mezzo, contralto, tenor, baritone, bass mold, regardless. There is little formal training to become a “baritenor”, even though that is the most common category for a male voice on Broadway at the moment. [A baritenor is a high, light baritone or a chesty, full tenor]. Same with the women — there are few roles for very high soprano [Christine in Phantom was probably the last one]. And there were never a lot of roles for mezzos or contraltos, so that hasn’t changed. [I guess “Gary Coleman” in Avenue Q is a contralto, but s/he is a belter, so that’s not the same thing]. The young people are relieved to have training that is geared towards making the sounds they hear on recordings but they also like the idea of keeping some of their more formal vocal production (just in case). Why not? It isn’t necessary to choose until and unless you get a role in a show that asks you for a specific sound, and even then, you can vocalize one way in the morning and a different way in the afternoon before the show, and survive very well. Life experience talking there, not theory.
There are also people who want to sound bad. It is, to them, some kind of a signature sound. There are people who have no choice but to sound “bad” as they have vocal injuries that are permanent. There are people who can sing high but don’t because they don’t like it. (Beats me, but true).
The current necessity for most singers, male and female alike, is to belt and belt high. It is absolutely possible to train someone to do that, most especially a student who has a good sturdy voice in the first place and who also has a nice sturdy body to go with it. Other people can learn but they are the easiest ones to teach. How high is high? What is the correct range? What is appropriate? The answer is, whatever the person can manage.
High notes always were money notes. They still are. It’s just that mostly, they sound a whole lot different than they did 50 years ago.