Yes, from what I understand, the Chinese expeditions were in part to refine the maps they had. Exploratory efforts were withdrawn because of internal conflicts, as I said before. The records were suppressed, the fleet was disbanded, and the faction in charge after the changeover decreed that no more expeditions were to be sent. It stuck because, unlike Europe, China’s vast territory, resources, and population were under central control. A similar circumstance in Europe would have been if no one else had ever gone west, even when Columbus came back and reported on what he’d found, because the Pope said not to go.
We weren’t talking about what did happen, we were talking about what could have happened. If it had not been for the wrong faction losing, the Chinese could have found the Americas first. If the Europeans had concentrated on the Oriental trade routes for another century, it could have changed the balance of politics and the Chinese could have started sending out expeditions again, before the Europeans started going west in any numbers.
What did happen wasn’t necessarily fated. There are always little turning points in history where things could have changed quite dramatically if the timing were a bit different. Also, nothing happens in a vacuum. Things happening literally on the other side of the world can have profound effects on places that don’t even have any direct contact with those involved. A slightly longer period of European explorers concentrating on Oriental trade could have affected politics all across the area and given the Chinese both the incentive and the time to find North America first.
Like I said before, they probably wouldn’t even have known it for decades or even a century, until the people with access to information from both Chinese and European explorers were able to compare notes, or until land explorations brought them into contact.
Japan had maintained intermittent trade with the Chinese, so at least Japan was out west. It wouldn’t have taken much to follow the line of islands looping from Japan north northwest across to Alaska. That wasn’t the way the Chinese did go, but they had a very brief time of exploration and fewer stories of cool stuff out there over the horizon to intrigue them than the European powers did. Fifty or a hundred years could have made a big difference in how things turned out.
The Chinese could have gotten another fleet together and come into contact with Japan during the Sengoku Jidai, when things were unsettled and the political situation was fluid. Their influence would have changed the course of several conflicts, possibly leading to a faster unification or a longer period without central rule, and in either case, there would have been a much better chance of the development of trade than happened under Oda Nobunaga or the later Tokugawa Shogunate. It could also have brought them into contact with Europeans in a different way as the Portuguese began arms trade with Japan around this time.
After firearms were introduced, Japan refined them, and their designs were superior to the European ones for quite a long time. Japan could have started exporting arms to China, which would also have changed China’s history, making the internal situation more chaotic and leading to more importance being placed on trade to the west.