No, Apple doesn't approve your company first. You simply sign up as an individual or as a company and then you get to generate certificates which you can then use to sign any application you want.

And by default, you can simply hold down a shortcut key to open an application and install it anyway without a signature.

So what is the point if Apple doesn't even verify your company?

As for the shortcut keys, I can never remember them.

The point is this: if malware is published using your developer certificate, then Apple can simply revoke the certificate and by default, users won't be able to install or run your applications anymore.

As for the shortcut keys, they're documented, so you don't have to remember them.

As noted by binarycrusader, no approval is necessary. It's just like signing a Windows application (also a damned good idea) and counter-signing it with Microsoft's cert. Both of these things make it so that your app can be flagged if you demonstrate that you're dangerous. The main difference is that Apple has it somewhat easier because they are the CA for the app certs.

As far as who develops apps for "classical" computers…there's a lot of us out there, because they're not going away.