Thank you for raising this very interesting and stimulating question, which is not at all stupid. In fact, I am somewhat embarrassed to say that the only answer I can think of is that “no one ever thought of it before.” WordPress version 3.5 introduced the Media Manager with its Modal Window and the thumbnail image grid for finding images and adding them to posts, pages and galleries. The toolbar at the top of the Modal Window lets you filter the grid by MIME type and “Uploaded to this post”. Media Library Assistant (MLA) adds the ability to filter by date and by category/tag.
The search box in the upper right corner lets you search the library by keyword; this is the closest thing I know of to finding an image by file name. If the title, caption, description or ALT text fields you have assigned to your images are useful for finding the image you want, that is the best answer to your question at this time.
You could use the IPTC/EXIF mapping feature in MLA to copy the file name into the title, caption, ALT Text or Description field and then use the search box to find the right image. Let me know if that would help and I can give you more specific instructions on how to do it.
There is no current setting or option that will give you a list that includes the file names of your Media library items, along the lines of the “Details” or “Content” views in Microsoft Windows. It seems like a perfectly reasonable feature, but it just hasn’t come up before.
I will investigate the possibility of adding this capability to a future MLA version, and I will leave this topic unresolved until I have progress to report. In the interim I hope you can find a way to use the category/tag filter and/or the search box to find the images you want. Thank you for your understanding and your patience.