Us older guys discovered long ago that the more hours/week beyond a certain amount you work, the less you accomplish.

Besides, I write my best code when I'm jogging. I just type it in when I get back to my desk.

I'm probably old by Valley standards (32), but I took a lot of crap for this view in my twenties. I worked for a consultancy that made money by billing my time out. They'd never tell me I had to work more, but it was heavily implied on multiple occasions that working beyond 40 hours was preferable. I asked why, as I had a series of successful deliveries, and stayed ahead of my workload. They would always terminate the conversation there.

You have to play close attention to the incentive structure of the business. The situation is arguably worse for startups if you're salaried: you're 'changing the world' so it becomes OK for the occasional 50/60 hour week.

But why do they care so much about hours and not about output? I would kind of understand if this was for some web technologies since older devs might not be up to speed with the latest compile-to-JS language but I can't imagine that someone who has been writing say C++ for the last 20 years would not perform better than someone fresh out of school.

The short answer is that they can't measure output. It's extremely hard for a layman to know exactly how much value he's getting out of a programmer except through another, more skilled programmer.

There's probably a business idea there.

Most starts ups aren't using C++. 90% of starts up do the "latest compile-to-JS language" thing.

That's because 90% of startups have only the most shallow bit of innovation going on, but they want to seem hip and au currant.

So they use whatever the latest angular clone is.

I think a much more charitable interpretation flies: there is a reason people invent new technology (it's better on at least one dimension than the old), and startups aren't held back by legacy considerations.

Well AFAIK FB uses C++ and they are mentioned as one of the companies using these hiring practices.

I would not call Facebook a start up anymore. They are creating their own VMs and Database systems. Most start ups don't do that. Unless that's the product.

Well I didn't call them a startup. And they are creating their own VMs and DBs which is even more reason not to hire only devs who are fresh out of school.

I did specifically state start ups. I don't live in san fransico/silicon valley, but where I live the vast majority of developers are working for small start ups and small businesses and not the facebooks of the world.

Its not meant to be accurate sampling, its hyperbole to prove a point.

But you can see for yourself. Have a look at most jobs at start ups, they're always javascript/ruby/python/fancy new framework or mobile apps to reinvent online shopping or web site analytics or something.

You characterize the popular startup languages as being "compile-to-JS" to prove that they're all mostly in the family of dynamic scripting languages?

No. To state they are mostly trend based, and superficial.

Hey, leave Python out of it :)

Because half of these guys are under 30 and they don't want to hire someone who reminds them of their dad.

Which, ironically, is tied to the conventional management view that butts on seats equal productivity.