A handful (probably already the maximum that the model supports) of websites can get by on donations (and then have their hands tied as to how to use the money,

A handful (probably already the maximum that the model supports) of websites can get by on donations (and then have their hands tied as to how to use the money, potentially preventing expansion or major changes), and a website that's nothing but "<primarily offline company>'s website" doesn't need ads or anything in the first place because it's just for information on the main business (but if they'd profit more from running some ads on it I wouldn't blame them; optimally that would lower prices but in reality it would just go to the CEO's bonuses); these do not disprove that the ad/subscriprion models are the most viable way for most internet businesses to operate.