I’m not convinced that the hardware is the real limitation (you can also for for example a real old Logitech Touch or older RPIs as LMS server and client with thousands of tracks).
It seems for me more, that (I’m now developing near 40 years hard- and software) there is a limitation in the developer and design resources…
Also I using the Rose primarly as Roon endpoint (otherwise I’d sold it) , but it has to work also as a standalone device (also as backup in the case you’re offline).
Because you can’t use the Rose as gapless UPNP client (no openhome integrated), you’ve to use directly connected sources and so for larger music collections, the search functionallity for which you need a scan, is a must.