>During boot, for example, even modern Windows boxes show a BIOS screen followed by a brief blinking cursor before the Windows graphics mode takes over.
This hasn't really been the case for more than 10 years now. EFI based systems will boot without changing display modes. Some hobby custom PCs might have compatibility modes enabled, but any laptop or prebult system is going to go from logo to login without flickering.
Statements like that pop up in quite a lot of programming blogs like these, they used to annoy me more until you realise it's less gloating and more naivety from the 16-21 age bracket with less "professional" experience.
This hasn't really been the case for more than 10 years now. EFI based systems will boot without changing display modes. Some hobby custom PCs might have compatibility modes enabled, but any laptop or prebult system is going to go from logo to login without flickering.