Only for clients with shortsighted devs. If they’re smart, they’ll see the flaw in that thinking and come up with better ways to monetize their client.
Actually I aggree with @semisol on the front that we need to find a sustainable way for zapvertizing. Zapvertizing can benefit the user who gets it. So also users shall fight for this, or you will be advertized to in different ways and you won't get a penny for it. We are in this together, so we shall find a way together.
I mean advertizers won't advertize if they have no benefit. And if advertizers have no benefit, users won't have either.
And if clients don’t have users because they decide to blanket their apps with ads, then those clients won’t matter either. I have complete portability of my social identity and content on Nostr to move to another client that serves me better. It’s your job to create a client I want to use and has a sustainable business model for you. If that means charging me to use it, then make it something I want to pay for. That’s up to you to figure out.
I think you can also add a bit of "love" and kindness to this as well. At the end we are human beings, and if we are kind to eachother, we incentivize the other side also. So being a user, you can also take part in, with not only joining, or not. If you just join or not, the progress will be slow. The more we work together, the faster we can be. Maybe I am fully wrong.