Well, the days of tanks as a mean of pure infantry support are over since WW2.
The advances in technology allowed the modern tank to include all three mentioned primary capabilities (protection, mobility, firepower) whereas in the beginning of tank warfare the technology to merge these design features in one vehicle just weren't there.
As for the big gun. It has always been the case that it is a tool for multiple roles and only the fear of the red hordes led to a fixation on AT ammunition in some western designs (not in the east). This is no longer the case. There has never been so many non-AT rounds available to modern tanks than right now.
And why do you talk of bringing a big gun to an infantry fight? Why do you think a modern war will be an infantry war? Light or motorized infantry can't stand against heavy forces in anything but heavy terrain. A HBCT eats a SBCT or an IBCT alive if caught in the right terrain. The gun of the MBT ensures that the spearhead vehicle of a heavy unit has a weapon which is effective against all kinds of ground targets.
The advantage heavy forces offer in favourable terrain are anything but small and will remain so for some time.
And a heavy combined arms brigade doesn't just consist of tanks. It's combined arms for a reason and there is enough other stuff in a HBCT that can kill infantry (Apart from programmable 120mm HEs and coax MGs slaved to a modern FCS...)
The advances in technology allowed the modern tank to include all three mentioned primary capabilities (protection, mobility, firepower) whereas in the beginning of tank warfare the technology to merge these design features in one vehicle just weren't there.
As for the big gun. It has always been the case that it is a tool for multiple roles and only the fear of the red hordes led to a fixation on AT ammunition in some western designs (not in the east). This is no longer the case. There has never been so many non-AT rounds available to modern tanks than right now.
And why do you talk of bringing a big gun to an infantry fight? Why do you think a modern war will be an infantry war? Light or motorized infantry can't stand against heavy forces in anything but heavy terrain. A HBCT eats a SBCT or an IBCT alive if caught in the right terrain. The gun of the MBT ensures that the spearhead vehicle of a heavy unit has a weapon which is effective against all kinds of ground targets.
The advantage heavy forces offer in favourable terrain are anything but small and will remain so for some time.
And a heavy combined arms brigade doesn't just consist of tanks. It's combined arms for a reason and there is enough other stuff in a HBCT that can kill infantry (Apart from programmable 120mm HEs and coax MGs slaved to a modern FCS...)