Right now, Your Music has a limit of 10,000 Songs.
We've recently reviewed this internally and at the moment we don’t have plans to extend the Your Music limit. The reason is because less than 1% of users reach it. The current limit ensures a great experience for 99% of users instead of an "OK" experience for 100%.
Please continue to add your votes to this idea in the meantime, as we're keeping a close eye on the votes and comments.