SOEs are 50+ years old, legacy titans like BYD ~30+, older than Tesla. Tesla tier tech upstarts nio, xpeng, li ~10. But ultimately who cares, the big / influential players are arguably too big to fail by local gov standards whose going to keep going forever, or consolidate under players that can keep them going. The brands too small to survive aren't seriously exporting to the west anyway (like yes there's brand/marketting plays like hiphi which is basically vinfast tier). Car makers, especially ones with tech stack are not Luckin Coffee, if state/province wants to keep a strategic brand going forever, they will. Just like western auto pork barrel due to "excellent" financiered bookkeeping and auditing.
Local gov can only prop up so long as they have money; and their balance sheets are strained due to ballooning debt funded by a deflated property bubble.
And just like the west, local gov they'll cut teachers wages before strategic industries. Debt crisis = local gov forced to deleverage because central gov chose to kneecap land finance, central gov can via many instruments find arrangement to prop up a player. Nvm these companies from tier1 GZ, SH, JS manufacture hubs with GDP the size of g20 economies, if someone wants nio and xpeng around and give them local robotaxi / fleet contracts to grift in perpetuity, or keep their self driving stack and consolidate manufacture and pawn off after market to someone else, they can. Keep in mind current auto involution = large players bleeding at rates where they still have ~10+ years of operational runway, these are too big to fail but cheap enough to bail size companies. Hence what is unlikely to happen, just like how other sovereigns fighting to keep their surviving legacy auto alive, is to let strategic auto die off in ether like mom and pop coffee shop. Except sovereign balance sheets (>100% debt to GDP) are in general much worse than tier1 PRC (<100% debt to GDP) even with squeezed land finance, aka western countries propping up western auto is a much harder lift than PRC local gov propping up local auto.