We do optimize LaunchBox but the primary focus of this optimization is speed and responsiveness of the application not memory usage. If we can limit memory usage without impacting speed of the application or it's responsiveness we of course do, but if either of those have to suffer we generally select to go the way of speediness/responsiveness (within reason).
Memory usage has gone up since previous versions because we have to cache more information than in previous versions. LaunchBox tends to also use more RAM because it caches more information in memory to help with importing and scraping speeds. It also can be set up to display more images at once time then most themes in Big Box which have to be loading to memory to display in the application.
RAM is by far the cheapest and most abundant resource a computer tends to have (save maybe hard drive space) and so optimizing strictly for less RAM usage would cause a lot of issues within the application and make the whole product EXTREMELY sluggish and increase the time it takes to do even the most mundane functions of the application by a pretty considerable amount. We have to make decisions constantly about whether to increase memory footprint OR increase performance, and when we have to decide between the two performance will win almost every time.