re: What popular bands still tour with little or no original members?

I don't know how famous Tangerine Dream is (their best-known work is probably the theme from Risky Business), but their lineup is pretty well-known for its near-constant turnover since they debuted in 1967. Their founding member, Edgar Froese, died in 2015 and had a hand-chosen successor to carry on after he passed away. Their most senior current member joined in 2005.

They're not only still touring and recording new material but they remix their old material too. Really neat little arrangement those guys have.