New Family Sharing account does not create shared Photos/Reminders/Calendar

After performing the troubleshooting steps above, I scheduled a call with Apple support and walked the technician through the problem and the steps that were taken.

• I was asked to perform the additional step of enabling Purchase Sharing. Neither of us expected this to work, and it did not.
• I was then asked to provide a link to the documentation where the expected functionality was described, and he was surprised to see that I was quoting from https://www.apple.com/family-sharing/ and not an outdated knowledgebase article.
• The technician asked for some time to consult with a peer and review internal documentation. He was able to find an internal document stating that this was expected behavior, but was otherwise vague on details. He explained that he has come across this sort of verbiage before, and that it is often a step toward functionality being deprecated within Apple software.
• He informed me that all he could do is provide some internal feedback about the missing feature still being described within the marketing materials. It was very unlikely anyone would be getting back to him personally in response, and that we were effectively at a dead end on troubleshooting the issue.

It's odd that I don't see more postings about this situation when trying to research the problem via search engines. I see two possibilities at this point:

1. The technician is correct and this feature has recently been deprecated. It's weird that more people aren't complaining about it, but apparently I'm one of the few people who decided to wait until late 2021 to set up Family Sharing on an iPhone.
2. My Apple ID has somehow bugged out, and the technician found a vaguely worded internal bulletin that caused him to give up on troubleshooting too quickly.

I'm leaving this Q&A open for two weeks in the off chance that the support rep was wrong and another user is able to identify a solution. Worst case scenario, I'll accept this as the answer and the Q&A will save future users from spending unnecessary time on this problem in the future. (at least until Apple gets around to updating their marketing materials)