Yes, MesoAmerica would keep advancing at it's own pace. Unfortunately, that pace was significantly slower than the pace of Europe, and especially that of Europe with borrowing from India, China, the Middle East, and to a lesser extent Africa. As a couple of others have said, the New World was falling further behind the old one as time went on. That might have changed to some extent when Peru came in more sustained contact with MesoAmerica, but at best they probably fall behind at a slower rate. The Old World just had more resources--more easy to domesticate plants and animals, more room--over twice the land mass if my back of the envelope calcs are correct, to support bigger populations.