I should mention that before the rise of the player’s union under labor attorney Marvin Miller, players were discouraged by management from revealing or discussing their salaries as this would provide in incentive to drive up wages.

I haven’t found any centralized database of salary information dating back that far. I have found alot of cumulative data on team revenues and overall player salaries in books by Andrew Zimbalist and Gerald Scully on baseball and economics.
Additionally, many players have revealed their salaries in their autobiographies (Cobb, Bouton, damn near every biography I’ve ever read on baseball), but I know of no single place.

Good points. Scouting is critical.

Steinbrenner went completely nuts after the 1981 WS loss, and then arrogated too much power to himself.

Is there comparative payroll data for the ’50s and ’60s. I’m searching Baseball-Reference.com, but I can’t find it.

Absolutely (bearing a resemblence to Cashman’s contemporary situation). However, I would argue that he combined greater financial resources with a great deal of precision and financial accountability (unlike the Steibrenner ’80′s, the Phillips/Duquette/Minaya Mets, etc.) as he assembled an elaborate farm system and number of working agreements with minor league teams that filtered a tremendous inventory of talented players to the Yankees.
For example, in the first half of the ’50′s, the Red Sox had a comparable lineup to the Yankees, but their depth in bench and pitching was nowhere near the Yankees. I attribute this to their never ending supply of minor league talent. I will of course stipulate that they did buy some high-end amateur talent (DiMaggio, Lazzeri, etc.), but many of their amateur acquisitions were a result of an extensive scouting network and a belief that signing a large number of relatively inexpensive amateur players will ultimately yield a sufficient number of quality players to compete. Not all teams could invest in such a system as a large difference in teams revenues and ownership wealth existed (see the Browns, Senators, Braves, Phillies), but the point is that Weiss placed an emphasis on this long-term, self-sustaining approach.
Perhaps I’m still bitter at the Steinbrenner ’80′s.

Don’t you think that a large part of the reason why Weiss was effective was that he could sign pretty much any player he wanted?

In my original post on this subject, that historically most common given reason is the one I was arguing against by claiming that the Weiss departure weighed more heavily than the instituting of the draft (Not to say that the draft had no deleterious effect).
Interestingly, the uptick in talent procuration from Latin America in the ’80′s brought baseball somewhat closer to the ’30′s-’50′s as teams such as the Dodgers and Blue Jays principally built their organizations on Latin American talent that wasn’t subject to the American draft. In this “Wild West” time, the most innovative, effecient, and locally connected teams were able to gain a competitive advantage on their deeper-pocketed brethren who lacked the vision to see this repository of talent.