Astrodome would've been demolished by explosive in the middle of a suburban car park.
All the CityPlace glass towers, tightly packed around the dome would instantly shatter. This is the reason given by Rogers that it would cost too much to demolish which is why they've been renovating it instead.
A SkyDome demolition would have to happen by hydraulic demolition hammers which could only run during the day and would take years. Nobody would accept that, even in daytime. It'd be a political nightmare. SkyDome is protected by CityPlace. This concrete bunker will be with us for decades.
If the Jays want to play somewhere else, the SkyDome can be converted into a convention centre which, coincidentally we're going to need as the MTCC is destined to be replaced. Replace the seating rings with convention rooms and amphitheatres and amenities like restaurants and hotel rooms, while the field with the seats removed could remain largely untouched as a showroom floor. Whether there'd be a need for movable roof is up to thinking of creative summer uses or it can be replaced with a fixed glass skylight.