No, this is hindsight bias. Dropbox did seem like a bad idea for exactly the reason you mention. There was barely an idea there because it was wholly unoriginal.

Dropbox's execution was better, and that's why they got traction from the first post.

And the timing was right, because there was a long term user base change starting around then. In 1998 or even 2003, most people only had one computer or internet device. In 2008, most people had multiple devices, so even if you weren't collaborating with anybody, you need something like Dropbox.

Stripe seemed like a bad idea because payments are probably one of the hardest things for a startup to tackle -- it involves a lot of regulation and fighting fraud and hackers (see all the BitCoin startups which have gone down in flames). People assume that Google or Apple would be better at doing payments. Stripe's execution is also way better. Maybe they have some other secret I don't know about.

The blog post sort of hints at it: do things in an hour, not in a week. But it should be obvious that you just have to be a better programmer, designer, and marketer than anybody else. :) And you have to work really hard, which it says at the end of the post. This advice isn't a shortcut: it's on TOP of simply being good and working hard (which are necessary but not sufficient).

Seeing some of Stripe's recent launches reminds me of Google in 2002. The quality is plainly there, and it is head and shoulders above the vast majority of startups. They are tackling a harder problem and doing it better.

So I think "bad ideas that seem like good ideas" is spot on. But there are multiple reasons things can see like bad ideas: 1) already been tried, 2) too hard, 3) big company will crush you, has more money and connections, 4) will take too long (for non-software startups, e.g. Tesla having to build factories and so forth, ... and many more. So it's "meta-advice", but still very accurate.

EDIT: I will also add that Dropbox seems like a bad idea because it seems like anybody can do it. Lots of experienced programmers say: "Oh it's just copying files. I can write that in a weekend".

It doesn't appear that there's room for great execution. Lots of programmers don't think it's worthy of them, since they are used to syncing files with their own tools. Why would you need to be a great programmer to create Dropbox?

But it turns out it's a lot deeper and harder than people think. I think there are lot of things like this. Any old programmer can do a 50% job. But to solve the whole problem takes a world class founder and team.

And of course the difference is you get $0 for the 50% job, but billions of dollars for the 100% job.

I've read comments talking about Joel Spolsky, saying: "Why should we listen to him; he makes bug tracking software?" Because they think bug tracking software is unworthy.

Joel is also super sharp, and that problem is worthy of him and his team. He knows something you don't know. If you do the math, I think it's clear that Fog Creek was pulling in early-Google-level profit per employee, with bug tracking software.

A problem is only as hard as the person who does it. If you are that great, you should be able to solve a problem with 10x or 100x less people, and reap the corresponding profits.