I find this thread so very interesting, my children are all grown and for the most part I couldn't even get them up out of bed let alone anything else.
But what I find interesting is that way back, yeah I did say way back whenever I was in school we just voted in the cheerleaders and of course anyone could try out but the school kids all got one day to vote for their choices of their cheerleader, and of course the most popular girls got the position. Is it not the same way now????
How many hours does this take up a week? A lot of things have come a long ways since I were in school and you just had a simple pep rally back them nothing more.

When I was in high school we had to endure both judged tryouts and a student body vote. They announced who made it through tryouts over the intercom on a Friday afternoon, then the next week was a full out campaign with a student body vote that Friday. Winners found out they made it by being "kidnapped" by the previous years seniors and taken to breakfast, dressed up, etc. (I had to wear a sign saying I would sing the fight song on demand) and taken to school for the day.
Talk about ensuring maximum humiliation for everyone involved.
Back then we just had to pay for camp, shoes, hairbows, and any extra matchy-matchy stuff we chose to get for pep rallies, etc.
It's much different now. DD cheered for a very competitive high school squad. You should have seen the contract parents had to sign, and the one for the girls was even more extensive.
Being an active member of the booster club was mandatory for parents. The booster club paid the school for gym time, purchased equipment and uniforms for the cheer program (the girls did not keep the uniforms). We also paid coaches salaries, their membership fees in national cheer organizations, their travel expenses, etc, etc, etc. Lets just say it was very, very expensive for DD to be a high school cheerleader.
Time commitments vary dramatically from school to school. The kids at DD's school called the coach "the cheer nazi". Of course I was always appalled by that title and felt it was extreme... until we got involved with the program. I'm still appaled by the title, but I have to say I understand how it originated now.
Summer practices were 2 hours every morning, Monday through Saturday, and they started at 5am. During the school year the girls had to commit to practice after school every day. Sometimes practice went for 2 hours, sometimes for 4 hours, occasionally even longer. The worst thing was that they never knew going in how long practice would last. 2 a days (both before and after school) were not uncommon during competition season.
One horror story: at one mega-long after school practice coach was in her office holding one on ones with some of the girls (dealing with cheer drama), so DD got the assistant coach to OK her leaving practice so she could get to work on time. When coach found out DD left practice without talking to her first, she called both DD and her boss, screaming that if DD didn't get back to practice she was off the squad. Of course by the time DD got back to school practice was over anyway.
Thankfully DD worked at a gymnastics studio where this coach was well known, so they covered her class and let her go. They just added the incident to their stack of crazy cheer coach stories.
Of course I think programs/coaches as intense as my example above are probably the exception rather than the rule, but cheer in general has definitely changed and become much more demanding over the years.