I am not sure if advertising is a necessary evil. I guess I do not like being sold something constantly, and when I am in the market for anything, I will expose myself to advertising willingly, but it is, in way, a matter of consent. I can imagine that there is also people who like being sold things unsolicited, you know, they might say that they like discovering new products through advertisements.
I’d buy a Nokia flip phone immediately if HMD would stop locking the bootloaders of their KaiOS devices. Great little gadget, very little customizability.