Not OP, but I think the BRICS+ are seeing continued development of productive forces (e.g. BRI; financing via the BRICS new development bank for industrial development [and not predatory credit issued for the purposes of lowering prices of export commodities thus stifling development]), while the G7 is unable to break free from neoliberal post-industrial services which have very limited real economic benefit, and in the case of Germany and presumably other west European countries, actively deinduatrializing.

I can't point to exact sources but this is Michael Hudson's bread and butter.