That's simply unsustainable long-term. It happens to work today that you can trivially block them at the network level, because they're still unsophisticated about how ads are delivered, in this still mixed open-Web-transitioning-to-closed-Apps world.

Long-term, ad-serving becomes more sophisticated, in-band, and indistinguishable from any other App data over an encrypted stream with the App vendor and/or walled-garden provider, or just bundled with the now-normalized constant App "updates" without the need for network access when displaying them at all.

You're on the losing side of an arms race when everything's closed.

Even if you prefer living in walled gardens, preserving the open Web escape hatch does a lot of heavy lifting in the checks and balances department. If it's entirely deprecated by society, the walled gardens will get exponentially worse with their increased leverage.

I'd like to mention, that I don't prefer closed gardens and out of principle don't use anything app only. My phone is for calls, the bath, and my bed. Plus the rare traveling.