And since the Trinity's works, by dominating CM, necessarily ate/eat into the playing time of other compositions, including Tamil ones, identifying the Trinity's language preferences as one of the causes for Tamil's exclusion does not appear far fetched to me
Vijay, it may not have been apparent from my 'systemic' ramblings, but we are on the same page on this one, as long as your point is a description of the concert scene in Madras in the early to mid 20th century. As I wrote before, there was a whole sequence of events that provided the fertile ground for the dependent evolution of Rasikas' tastes & preferences, and the availability of compositions from the Trinity. Add to that all the specific players and social circumstances described by CML and Arasi. Once the CM system got into an equilibrium state with that 'tight-lock' among rasikas, sabha management and perfomers, it tended to stay in that state until some external disturbance of sufficient magnitude caused some chaos. The system then settles in to a new equilibrium. That is how I view the effect of the 'Tamil Isai Movement' as that disturbance of sufficient magnitude and the resulting new equilibrium where singing a few tamil songs is accepted by that triumvarate of Rasikas-Sabha Secretaries-Performers. You need another disturbance of sufficient magnitude for a new equilibrium that includes Secular compositions.
The fact that the trinity were contemperaneous is in itself a statistical quirk. To add another set of equally qualified composers in the same time period and in the same language would compound it manifold. And if indeed they did, that their work was, for some reason, never discovered, even more so. And we must remember that Tamil composers from that era - be it GKB or Arunachala Kavi - while not as popular as the Trinity, were not unknown either. And in my very guarded opinion, composers of great merit but nowhere near the Trinity.
Following are just some comments on your comments to illustrate my 'systemic' analysis of this situation. Just to be sure, these comments are not to undermine the compositional genius of the Trinity ( who am I to do that? and also I do personally think they were geniuses ) nor I am carrying water for some unknown/less known Tamil composers. In fact it is outside of such value and aesthetic judgement of the Trinity. It is all about how to think about the Past based on historical narratives which are by definition very compressed.
What you call as a statistical quirk is really not a statistical quirk with respect to their birth and living comtemporaneously. Why? Because, there are always geniuses living contemporaneously. In the whole population mix, that is not an infinitessimal probability. Addressing them as Trinity by grouping these three together is something that later generations did for whatever reasons they saw fit. That is what gives us the illusion of a statistical quirk.
Another related point is: Our current value judgement like 'merit', 'relative difference in quality' etc, need not have anything to do with the reasons for winners and losers of the past. Let us take for granted that winners win out based on merit. But that does not necessarily mean losers lost out because their works were inferior. We are all susceptible to that implied and unconscious bias, that is the 'survivor bias' with History. The environment and the multitude of other causes prevalent at that time caused the losers' works not to be propagated to the future generations with as much vigor as the winners. That is the only thing we can infer from compressed Historical narratives. Is it possible that they did not rise to the prominence because they were inferior? Yes, definitely but a few centuries later, lack of any specific details, only if our definition of 'inferior' is same as 'whether they survived or not'. That is basically a cyclical statement and by definition it is true. This is the flip side of 'survivor bias'. We can call it the 'loser bias'.
I am stating all this abstract stuff to just describe one point about these kinds of things. I started in this 'complex system' way of looking at the past when you stated in passing "[ lack of Tamil preemminence is a ] result of a remarkable efflorescence of compositional genius in other languages". The key words are 'remarkable efflorescne of compositional genius'. The past does not necessarily produce losers based on our current view of 'genius' let alone the definition of 'genius' prevalent at that time. It is a result of the complex ecosystem prevalent at that time consisting social, political and cultural sub-ecosystems interacting in complex ways as they always do. Not any different from how things happen today about today's matters.