If only miners run nodes, and no one else can access the chain to fully verify it, then the chain is not needed.
Dude, merchants or users don't need to verify the whole chain, where have you been all these years when people talk about SPV wallets, mining and non mining nodes, etc?
-Čuj, dodaj mi pilu. -Sorry…. -Pilu, čovječe, pilu. -Sorry…. Sjeti se jedne rečenice iz filma. -Do you speak English? -Yes, yes! -Pa onda mi dodaj pilu!