Tanks are terribly vulnerable without infantry to protect them to the extent that I would suggest that if hostile infantry get into base contact with a tank which has no infantry to protect it then the tank is an automatic kill. Tanks need infantry far, far more than infantry need tanks especially in FIBUA/FISH where the tanks are not operating in a suitable environment. I was chatting about this recently with a former infantry officer who mentioned that on one exercise he had two Challengers as support but one had a mechanical failure and the other would not go on alone.
Someone made a case a while back for converting old redundant tank chassis to specialist vehicles for FIBUA whether as transports for the infantry or as specialist vehicles with high angle guns capable of firing a decent HE round. Something like a modern version of a Brumbar. The Israelis surprisingly found M109 SPGs very useful in FIBUA. Though they were very vulnerable they could elevate to hit targets far above where a tank could hit, very useful in a built up urban area, and the effect of a big 155mm HE shell was most impressive.
The Israelis have of course already done the APC conversion. For years they have done everything possible to minimise casualties and it looks as if the western nations are going to have to follow their example. Off hand the examples I can think of for this include the design of the Merkava with the engine in the front and a stern door – though this as much about resuppling the tank with ammunition as evacuating casualties; their very heavily protected APCs/IFVs built on old tank chassis and a drag handle on the back of their assault vests.
Sorry to harp on about the Israelis, I know a lot of people have problems with them but they have had a lot of recent experience of combat in general and FIBUA in particular.