Elon Musk wanted to make sure his newly won control of Twitter would ‘sink in’ as he staggered through the doors of the company’s San Francisco office with a heavy ceramic kitchen basin. He left it in the foyer with the photographers before beginning a programme of layoffs and policy changes.

What may have yet to sink in with Musk in the following months is not just that running a social media enterprise like Twitter is surprisingly costly and beset with social issues, but that a previous CEO wound up bankrolling what may turn out to be Twitter’s replacement in the market. If successful, it might take other companies of the same Web 2.0 generation with it.

Technology executives like to talk of disruption. To break through, they need to disrupt whatever is in the lead spot now. Disruption involves not just taking over the top spot: that’s just regular competition. Disruption means breaking the old business model so badly the incumbent has nowhere to go...