This is something that I have often thought about before. The major upheavals, as you point out would be way too short and abrupt to cause the kind of changes that macro-evolution requires. On the other hand, what kind of environmental changes do we have left that aren't simply fluctuations? I think fluctuations would cause adaptions that also just fluctuate rather than "small logical jumps" (such as the length of finch beaks, to use a worn-out example).
I agree with you on this. Macro-evolution probably would only work if there are continuous slow adjustments to the environment instead of fluctuations back to an equilibrium. And you are correct that we have either had major upheavals or fluctuations, but have not yet experienced gradual changes to the environment that keep going in one direction. eg continuously hotter earth, continuously more methane, anoxic oceans that keep getting more anoxic etc etc. The natural forces keep pushing the environment back to an equilibrium which makes macro-evolution completely unnecessary and accordingly not observed.
Nevertheless, that's not my point , so I will clarify what my point is. I used to be a mediator and one of the secrets to getting a healthy discussion is to acknowledge some points of the other. If you fail to acknowledge a point that is obvious to another person, you end up hitting a brick wall with them. So can't we at least say to evolutionists that yes, under certain conditions not yet seen on earth, it could be conceivable for the mechanics of micro-evolution through variation to result in macro-evolution? I really do believe macro-evolution is possible, and nothing anyone has ever said would sway me because there has to be a set scientific principle that makes it impossible, and such has not yet been put forward yet. Quite simply put, if variation works, and keeps happening in one direction slowly and carefully enough, we could conceivably (even if not practically) end up with an extreme variation that works. So why not stick to the truth, yes evolution can work from a biological perspective. Highly unlikely, but it can.