Newer != more advanced. ~20 years ago I remember people arguing that Latin American telecommunications infrastructure was "more advanced" than in the U.S. simply because per capita cellular usage was greater. If you Google that claim today, it's still being made regarding Latin America vs Canada. But what those figures actually represent is that their wired infrastructure is poor and unreliable in Latin America.
The degree to which an economy is "advanced" has more to do with institutional systems and processes, not whether they're using the latest tech. Often times the latest tech papers over institutional deficiencies, but only superficially. Mobile payment platforms have been ubiquitous in Africa for many years, but nobody would say that Africa's banking system is "advanced" or that it's capable of supporting the needs of an advanced financial sector. They became ubiquitous in Africa first precisely because of institutional deficiencies. Mobile payments solved some of the most visible consequences, but by itself it didn't go very far in addressing the underlying problems. Sure, it's easy to pay a vendor for lunch or a pair of sneakers using your phone, but what matters infinitely more is how safe and reliable it is to secure a $2,000,000 LoC to help bring your factory online.
Old systems in older economies persist because they work, or at least work well enough.
If China overtakes the U.S. in technology dominance, it's because they've spent 30 years studying, copying, and improving upon American legal, financial, and business management systems. Notwithstanding the fact that they are serving the interests and demands of the Communist Party, which often puts them in a lose-lose scenario, China's economists and policy advisers understand the systems of modern capitalism better than most of their Western counterparts.