There is tech, but oil as well.

It's both tech and shale oil that saved the US from the decline predicted at the end of last century.

Gemini says (20 years growth): - USA: 51% total, 27% without tech. - EU: 25% total, 21% without tech. - China: 345% total, 205% without tech.

A 'bubble bursting', if that happens, doesn't make the tech sector go to zero. Apple doesn't suddenly stop making iPhones. It would take a hell of a lot more than that for the US economy to fall to European levels.