Searching for purchased movies and tv shows

I've been using iTunes for movies and tv shows for years and now that I have a really big collection, it's getting harder and harder to look for film or tv show I want to watch due to Apple not supporting my purchases search function on iPhone, iPad and Apple TV.

Some films and tv shows go off sale time to time, though you still have access to them, the search function or Siri no longer looks for them witch means if you have 1350 movies and you're looking for Kung Fu Panda, you have a long way down to look for it. You can't use Siri or the search function to search for it as it searches the store and not your purchases so you'll be prompted to buy it again. Virtually almost every Universal Studios and DreamWorks movies (which are owned by Universal Studios), are unsearchable because they take their movies down every few months and re-list them again for purchase.

So why when using Siri or the search function to search for movies and tv shows it also doesn't search in your purchases? If you forget that you already own that specific movie, you'll end up with two copies of the same movie if you accidentally purchase it again because it's been re-listed. It would just prompt you to buy it again instead of searching in your purchases.

Another example is the TV App and the "Up Next" section. When watching a TV show, it displays the next episode to watch when you finish watching the previous episode and at the end of the series it displays an episode from the next series to watch. Now let's say you're watching Red Dwarf Series 10, at the end of the series it brings up the next series. The problem is that series 11 that I have already purchased has been re-listed so instead of playing that one next, it prompts me to buy it again.

All these problems are not present on Mac, so why are they on other devices, especially on Apple TV. It almost feels like it's there to make you buy the same film or tv show over and over again by making it hard to find the ones you already own.