[Buzy]

When you come to art, you'll generally get what you pay for. Most artists who do this professionally will generally calculate how much time something takes them and will adjust price in consequences. Or, particularly livestreams based artists, charges hourly.

Nobody wants to do produces something which takes them hours to produces only to make less than minimal wage.

There -are- people who do. But generally they are either :
A-People who do this in their free time and have a "proper" job. As such, they are often the kind of people most prone to drop a commission or taking commissions in general if it stops being "fun" and/or become cause for burn-out when trying to mix this with their main job in their schedule.

B-People who're new at this and are either afraid of charging too much and scaring away commissioners or just underestimate the time investment of a particular type of piece versus what they charged for. This is especially prevalent amongst younger artists who often think it will be a "fun" thing to do... until they get in over their head and/or either shape up or give up. As such, they are oft equally prone to giving-up/burn out than those for whom it's a spare time thing(which is often the case for the younger artists as well who are often taking such works while also at school).

As for comic pages just recall one fact: You're talking about a page with multiple panels. which might sound simpler than a multiple-page work and in some cases it might be. However, you're still basically talking the equivalent of multiple images(almost multiple "pages" in some case) in a single image, which can often actually prove to be additional(rather than less) work due to have to make/draw all those panels but also the additional challenge of composition and layout so the placement of the panel look good but also making sure the composition/layout of the content of the individual panels also look nice and good as well.

There's a reason most TF artists who've done comics in the past rapidly give up on comic as a commission despite how many praise they might have gone over them or at best make them a limited deal thing with few openings(and still relatively high costs). It's often just not worth the time investment for what people are willing to pay for them.