General information on US ebay site visibility

Hi,
since I know there are many users here who work on ebay.com website, I would like to ask them some information about listing visibility, since the ebay assistance, after months of requests, NEVER helped me (nothing new, the uselessness of ebay assistance is something worldwide known…).

Well, I would like to know why all my listings listed in ebay.it are not visibile in my ebay shop if I browse it from ebay.com. Listings are correctly showed from any other ebay site (Germany, Austria, UK, … also Australia). Only in ebay.com website it doesn’t work. If a customer visits my shop from US ebay, of around 27.000 acrive listings, he can only see some hundreds that I have directly listed in dollars in ebay.com site. All other items, published in ebay.it and ebay.de, are completely gone, nothing appears. I also published a question on US community here: https://community.ebay.com/t5/Ask-a-Mentor/ebay-listings-published-in-eBay-it-shop-are-not-visible-from-my/m-p/33252219/thread-id/280163 and a user found the issue regarding default item location search on ebay.com. This issue persists from at least past years and affects almost all sellers I checked for.

Now I ask, is it possibile that none before me pointed out this terrible issue? And none fixed it?! I am afraid this is the real issue of decrease of international sales. Any suggestions from users here would be very nice to hear. I am really pissed off…

Kind regards
Federico