Dear Garmin Please please listen to this sensible Junior member. Millions of us would like to track shoes - it is it only reason i'm maintaining a Strava profile..
Don't hold your breath. This is probably one of the oldest and most requested items here. A quick search will reveal people asking for this way back in 2009.:(
I highly recommend using RunningAhead.com as a secondary/alternate site. If for no reason other than ensuring you don't get screwed if/when Garmin f's up your data (see recent threads where people have LOST EVERYTHING). Clearly it is risky to keep all your eggs in one basket.
BTW, for the record I have no connection with RunningAhead.com other than as a user. I don't get anything at all if you use them other than the satisfaction of helping out fellow runners. If Strava, Runkeeper, TrainingPeaks, etc. are more to your liking then use those instead. Main point being don't trust all your data to one site. They might lose it. They might turn off the ability to export your data to another site. Imagine if you were choosing your next running watch and had to decide whether or not to lose years of logs?