There is Bridgy Fed, which bridges accounts over to the other side if they follow the respective Bridgy Fed account on their platform. This is opt-ín though, so you can’t just follow anyone, they need to have followed @ap.brid.gy on Bluesky. To have your interactions bridged you need to follow @bsky.brid.gy@bsky.brid.gy.
If the account you want to follow is not bridged and you are okay with just reading their posts, you can also use a service like RSS Parrot as every Bluesky account also serves as an RSS feed.
I don’t think that’s necessarily true. As fas as I know there are no plans to inject ads, they are planning to create a marketplace for custom feeds (think “premium” feeds) and labelers and such where they would take a cut. You would obviously still be able to purchase access to them from other servers. But this goal seems kinda lofty, not sure if it can be viable.