Thanks for laying out the context/framework/details! I guess the main question mostly pertains to the relatively speaking easy times period c. 1970-2005, then.

Thanks for laying out the context/framework/details! I guess the main question mostly pertains to the relatively speaking easy times period c. 1970-2005, then. What root constraints drove the maximum amount that (i-iv) could be moved forward with each shrink? In other words, what really governed or capped the magnitude overall rate of change? I naively/imaginatively wonder if the primary constraint was artificial in a sense, required to maximize long-term shareholder value (or a similar goal). Is this a reasonable query (if not, why)?