It costs a lot of money to run YouTube. If someone wants to make a competitor, they’re free to do so, but most will charge because of how expensive it is or you could use a PeerTube-like system. I pay for YouTube Premium and get value out of YouTube. I’m also an adult with a decent paying job so it’s not a big deal for me.
Maybe the mistake of these conglomerates is getting people accustomed to a certain level of service for free.
It's not a mistake, they do it on purpose. Most tech companies spin up with free offerings to acquire critical mass, and then pull the rug out from under their users once they feel like they can squeeze money out of them without scaring all of them away.
Social media does it (Reddit, Twitter). Video games do it (COD, yearly releases, DLC). eCommerce does it (Walmart, Amazon). IaaS does it (Heroku).
Don't give them the benefit that it's a 'mistake', it's very intentional. CAC is a metric used by all tech companies and is calculated to build network effects and large user-bases. I find it unethical and borderline fraudulent to build these community pillars and then defile them for profit. We'll be left with absolutely nothing free in life, no town squares and no transfer of information without fees.
Whether you or someone else can afford $10/mo is completely irrelevant.
It costs YouTube a lot of money because they pretended to be a free service and allowed anyone to upload enormous amounts of video data which they now have to continue storing and serving.
Maybe the mistake of these conglomerates is getting people accustomed to a certain level of service for free.