No. They were not there to replace tanks. They were to supplement tanks in urban combat. It's design was actually based on the Shilka which was used as an area suppression weapon in Afghan and the Chechen wars. Iirc it's stated official purpose is to supplement tank units in combat.
Sure it's a great piece of equipment but there are things to consider. Is the Tunguska superior to it in the SPAAG/tac-SAM role? If so then replace it with Tunguskas. If not then why have Tunguskas if older Shilkas with upgrades are superior? (which they're not
) Remember the Tunguska can be datalinked into networks. I would assume that it can be datalinked into an overall IADS along side with tac-SAMs, divisional SAMs, and even theater SAMs.