Remember that what we're essentially looking at right now is the question of whether or not VdA was attempting to take his club out of the American Association and join up with the Players Association. I think I've already shown that, despite his public statements to the contrary, VdA actively engaged in negotiations with the PL in December of 1889 and, if the Pittsburgh club had stepped aside or been unable to secure financing, the Browns (with, one assumes, their team intact) would have been playing in the PL in 1890.
What specifically would have motivated Von der Ahe to jump from the AA to the PL? We've already looked at a bit at the financial impact that the PL had on the Browns and the idea that, as a result of the formation of the PL and the loss of their star players, the Browns faced "financial annihilation." But the possibility of financial armegeddon was merely a hypothetical (although one I'm certainly VdA took seriously) and the longterm impact that the Brotherhood War had on the Browns and the St. Louis baseball market is something that we see in hindsight. While I have no doubt that it entered into his calculations, I find it difficult to believe that it was economics alone that drove VdA into negotiations with the PL. David Nemec, in his fine book, provides a bit of historical context that offers a more substantial reason for why VdA may have been looking at the PL in December of 1889.
...Association magnates felt they could put other matters ahead of the impending Brotherhood war when they assembled at the same New York hostelry a week later, on November 12 (1889). Topping the agenda was the selection of a new loop president. A cabal comprised of Von der Ahe, William Whittaker of the Athletics and delegates from the Columbus and Louisville clubs had already caucused prior to the general meeting to handpick a successor to Wheeler Wyckoff. Their choice was Louis Krauthoff, an officer of the Kansas City club, but Krauthoff spurned the invitation upon learning that he would have to agree to meet a certain condition-namely to exclude Brooklyn and Cincinnati from all important Association committees-before the cabal would push for his election. Von der Ahe's bloc then cast its weight with Zach Phelps, by this time the loop's attorney.-The Beer & Whiskey League
Hostilities opened when ex-Missouri congressman John O'Neill, there at Von der Ahe's invitation, nominated Phelps, and Byrne proffered Krauthoff's name. The two aspirants tied 4-4 on the first ballot. For all of the first day of the meeting and deep into the second day, the deadlock continued with Von der Ahe's coalition of St. Louis, Philadelphia, Columbus and Louisville lined up stubbornly against Byrne's foursome of Brooklyn, Cincinnati, Kansas City and Baltimore. Late on the afternoon of November 13, Byrne and Cincinnati president Aaron Stern were called out of the room by a messenger from the League, which was conferencing simultaneously and receiving periodic reports from a spy at the Association meeting. League titans were hopeful that the battle over the Association presidency would tip Brooklyn and Cincinnati over the edge...(Both) clubs could no longer benefit from the Association's major attraction to them. For Brooklyn, Sunday games at Ridgewood Park were certain to be problematic in 1890, and the Reds had definitely lost Sunday ball to the Sabbatarians. What made a new home in the League still more appealing to Byrne and Stern was knowing that Ward's insurrection would decimate the other League clubs while leaving their own relatively unscathed. Perhaps at Byrne's urging, the Cincinnati owner had also hastened to sign most of his key players to contracts for the 1890 season as soon as he saw the Brotherhood trouble brewing.
Half an hour after they had left the Association meeting, Byrne and Stern returned and dropped a bombshell on the assembly by tendering the formal resignation of their clubs from the Association. When they exited, with them went the delegates from Baltimore and Kansas City...Kansas City resigned from the Association and joined the minor Western League, taking its players who were either already under contract or else preferred to stay with the club and auctioning off those who wanted to stay in the majors. Barnie was mum on Baltimore's intentions, but it was presumed that the Orioles would also try to join the National League, perhaps by purchasing the Washington franchise. Sure enough, on November 30, Baltimore added its resignation to the mass exodus from the Association.
So by December 1, 1889, the Association had torn itself apart and was down to four teams. VdA essentially had three options. One was to join the Western League. This was an option that he had considered in 1888 when rumors circulated that the Association was about to split up upon geographic lines. The second option was to rebuild the Association which, of course, would eventually happen. However, this didn't take place until January of 1890 when the Association started to admit new clubs. The third option was to join up with the Players League. I think the evidence exists to state that in December of 1889, before attempting to rebuild the Association, Von der Ahe attempted to move his club to the Players League.
It's impossible to say what effect a Browns move to the PL would have had on baseball history but I don't think there's any doubt that the Association would have ceased to exist if VdA had been successful in his negotiations with the PL in December of 1889. Would the PL have survived after 1890? Would the relationship between players and owners have been different? Would the Browns still have ended up in the National League? Would the American League have ever existed? I don't have answers to these questions but I don't believe that the Association could have survived the defection of the Browns.