Yes the current prices are thanks to mass production in china, but he is saying that germany started to invest into the solar boom when prices where still high and without the boom might not have happened (that fast). E.g. in 2009 germany had 10GW [0] installed versus chinas 300MW [1]. But new solar installs peaked in germany at about 7.5GW over the next 3 years, among other reasons because germany does get significantly less sunlight.

[0] https://energy-charts.de/power_inst.htm?year=all&period=annu... [1] https://en.wikipedia.org/wiki/File:China_Photovoltaics_Insta...