I doubt Zelda had very much overt influence on RPGs. The clear influence on early RPGs would be fantasy novels, Dungeons & Dragons, the first computer RPGs, and, obviously, Final Fantasy and Dragon Quest. Of course, there could have been personal influences on individual developers, such as Ico being an influence on the writer for Half Life, but that does not seem to be what the person in question is saying, so I'll disregard that.
The argument for later RPGs turning to Zelda for action combat, as kind of a convergent evolution situation, makes more sense. However, I'd argue that parallel evolution is just as likely. Perspectives aren't invented, they're discovered--or, more accurately, they're first used by the people who have the necessary technology and skill and, even then, popular games are given credit over smaller games that did something first.
Of course, incidental influence happens all the time. Developers do not live in a vacuum. Elements are borrowed back and forth often. But Zelda making RPGs what they are today? I don't believe that. I think RPGs now would be roughly the same had Zelda not existed.