I mean, that's hyperbole. Even in a flash-dominated web, there was still tons of non-flash technology being developed and distributed. In 2023 it would definitely be obsoleted, if for no reason other than Adobe having no incentive to keep it around. Apple's decision feels tangential relative to the progress of internet bandwidth, delivery technologies and even just the plain advent of YouTube obceleting 90% of the places Flash was used.
Flash would be dead today even if Apple did adopt it, because nobody in the industry wants to pay arbitrary taxes or kiss the proprietary ring. Their freedom on the web let them evolve and pick competitive replacements; Flash's death is hardly a defense of iron-fist ecosystem enforcement.