I agree with the characterization of applications you've laid out and think everyone should consider whether they're working on a "tall" (most users use a narrow band of functionality) or a "wide" (most users use a mostly non-overlapping band of functionality) application.
I also agree with your take that tall applications are generally easier to build engineering-wise.
Where I disagree is that I think in general wide applications are failures in product design, even if profitable for a period of time. I've worked on a ton of wide applications, and each of them eventually became loathed by users and really hard to design features for. I think my advice would be to strive to build a tall application for as long as you can muster, because it means you understand your customers' problems better than anyone else.
I also agree with your take that tall applications are generally easier to build engineering-wise.
Where I disagree is that I think in general wide applications are failures in product design, even if profitable for a period of time. I've worked on a ton of wide applications, and each of them eventually became loathed by users and really hard to design features for. I think my advice would be to strive to build a tall application for as long as you can muster, because it means you understand your customers' problems better than anyone else.