The problem isn't the buildings themselves (which are not heritage and aren't worthy of preservation by any means), it's that new construction - especially investor-driven condos - don't provide the spaces for places like Sneaky Disease or The Real Jerk to thrive. Remember the hue and cry when The Real Jerk wanted to move into a condo's retail space, even when such a location *was* set up for a restaurant? The location The Real Jerk ended up at was a better fit - but that little plaza at Gerrard and Carlaw will probably disappear at some point too.
Music venues, good bars, many restaurants and the sort aren't welcome in condos because of noise concerns, and condos themselves are built in a way that exclude many other businesses with large wide storefronts (only to be blocked by Shoppers Drug Mart's window film), high rents, and poor layouts.
You want to ensure these types of places survive? Force developers to build retail spaces that can handle the variety of businesses that attract people to city living in the first place.