The reason Chinese solar outcompeted European solar is partially that China has real lower costs, but was more because China had way way way more appetite for massive subsidies to dominate the market.

They took over the solar market from Germany after Germany foolishly stopped subsidizing it and almsot overnight killed the thriving domestic solar industry.

Chinas solar panels are almost surely being sold internationally for less than they cost to make. If China stopped selling them and domestic producers sprang back up using techniques they've learned from the ongoing solar panel 'recycling' programs, the domestic solar panels would surely be a lot more expensive than Chinese panels, but they'd also almost certainly be cheaper than fossil fuels, and would find a place in the market.

Besides, the cost of panels isn't even the expensive part of solar installations anymore. The expensive part is the land, grid connections, and installation labour.