Should we all bite the bullet and create an app? And if we do, will that really help?
If you're a merchant and have an ecommerce site, I think at some point it will almost be a necessity - if only for customer loyalty. Smaller ecommerce sites will likely get most of their "first time customers" through search or other online marketing methods. But once a customer has ordered from the site, it just seems common sense to have an "app" available that the customer can download to use (if the customer so chooses).
That said, the app is in no way a replacement for a website that is fully functional on all devices (aka...a responsive website or something similar). Ecommerce sites in the future will, I think, want to have both a "mobile friendly website" and an app available.
For informational sites and blogs and such that rely on advertising, the answer I think is "it depends." It would depend on the purpose of the website, who its visitors are, if it is even possible to monetize the app (monetizing informational/blog apps doesn't seem easy at all), and a lot more site-specific things.
For my own informational site, I can't yet fathom how to make money off it if I put it into an app form - and putting the site into an app format would be a massive undertaking. But perhaps that will change in the months or years ahead.
We know it's been difficult for many to monetize mobile traffic: Small screens, fat fingers, tiny ads don't help, but even so, the CPC is lower, too.
I can't speak to other webmasters, but CPC on Adsense ads for me is extremely low. Mobile, while lower, isn't "that much lower" anymore. It's a case of the desktop/tablet sphere "catching up" to the mobile sphere - and not in a good way from the publishers perspective!
However, while Adsense and banner ads seem to convert terribly for me anymore, plain old boring text links seem to work wonderfully for mobile visitors. If you have an informational/blog type site, boring text or native-served simple graphical images with a short caption, combined with an affiliate link that leads to a "mobile friendly" merchant website, can work extremely well. On my own site, mobile conversions from these types of links are identical to desktop conversions. They are just a royal pain to implement, which is why most people probably don't do this.