I think they would. Toyota already had very good hybrid cars for years, so plenty of experiences with batteries.
Tesla made electric cars sexy, but I was always just a matter of time before electric would go mainstream.
I think the existing investment in tooling, plant and equipment that these companies have accumulated makes it hard to economically justify starting from scratch with new tooling, plant and equipment on a product line that has no competition. Tesla provided that competition, and justified such investment.