Some will never get warm enough. Others will be too hot. If your thermostat is in a room that has a cold radiator, your fuel bills will probably also increase because your burner will run longer than it should. You're also liable to get water hammer noise, especially if the asbestos abatement folks didn't do a good job of reattaching your pipe hangers. Sags in the pipes cause water to form puddles, and puddles cause problems in steam heating systems.
Insulation makes a huge difference when it comes to steam mains.
Here's an example. Let's say it's 50 feet long. That was pretty standard practice. When the air in your basement is 70 degrees, the heat loss of that insulated main is going to be about 2,450 BTUs per hour. Naturally, if the air in your basement is colder than that, the heat loss from the main will be greater, but let's figure that the air is 70 degrees, just for the sake of comparison.