I currently use vim every day. I have been trying to learn vim off and on for about 30 years. vi and vim have modes because they were created in an era where computing and terminal capabilities were very limited and even when the terminals could support interactive editing, it wasn't expected. They had very low expectations. They were used to things like 'ed'. The religious beliefs that programmers have about vim are…
vim was released in 1991. Same year linux kernel started and Apple PowerBook came out. Limited terminal capabilities is not the reason vim is modal.