>If the Economist makes such mistakes in their headlines what does that say about the quality of their journalism?

IMHO, it has always been crap, because of their biases, and pandering to their audience.

But that's beside the point. "Mistakes in a headline" happen to the best of outlets, and always have had. I assume you are OK with an outlet making a typo now and then, no? (There's even a name for this phenomenon, the "printer's devil"), and that making some doesn't mean the outlet's journalism is bad, right?

Your question would only make sense if they frequently made typos, and showed some huge careleness about it. Not something one would generalize from seeing this ONE mistake.

Anyway, this isn't even a typo or mistake. It's a well known expression. Wouldn't it be prudent to first look it up in a dictionary before questioning those that dared to use it? It just means that SV businesses are jumping in that particular domain (piling in: to move into a place quickly).