There was a major difference between the situation in Europe and the situation the Rosh Yeshiva found in America. In Europe the groundwork for Harbotzas Torah (Torah dissemination) was there. The concept and ideal of studying Torah "Lishmoh" - Toras Hashem for its own sake - because of its inherent value as the word of Hashem - was ingrained in European Bnei Yeshiva from the time of Reb Chaim Volozhin, the Vilna Gaon and before... Not so in America, however.. The concept and, all the more so, the practical possibility of devoting many years in Yeshiva and in Kollel to total absorption in Torah lishmoh... just didn't exist. If one did study longer than the norm in Yeshivos it was in preparation for a career in Rabbonus or Chinuch... What [Rav Aharon] brought about was a spiritual revolution both in the American yeshiva world itself, as well as in the minds of American philanthropists, to whom the entire idea of authentic yeshivos on American soil, particularly the novel idea of studying Torah lishmoh after marriage, was outlandish. (pp. 12-13, 40)
But it wasn't just 20th century Americans who would have considered the Lakewood kollel model to be outlandish. Contrary to the impression given, that Rav Aharon brought the classical, traditional, authentic kollel model to America, he actually invented it.
Historically, the term “kollel” referred to communal bodies or to communities. But in the nineteenth century, it was given to a new type of institution, in which married men were paid a stipend to continue their Torah studies. The first such institution was founded in 1879 by Rabbi Yisrael Lipkin (Salanter) in Kovno, with the support of Rabbi Yitzchak Elchanan Spektor. But it differed from the modern kollel in several significant ways. The studies were focused on halachah rather than Talmud and culminated in rabbinic ordination. The students also apprenticed to community rabbis, learning how to deal with halachic questions and procedures. There was a three-year limit to the program, by the end of which the student was to have acquired a rabbinical post; some were being prepared to be rashei yeshivah, but most to be community rabbis. The students were spread amongst different study halls and supplemented their studies with local adult education, so as to strengthen the local communities and gain experience in “practical rabbinics.” The network of Noveradok kollels later established by Rabbi Yosef Yoizl Horowitz was likewise specifically oriented towards training rabbis and strengthening Torah study in local communities. Similarly, in the Slabodka kollel that was established after World War I, members had to make a commitment from the outset that after five years they would gain ordination and fill a rabbinical post.
In marked contrast to all these was the type of kollel first established by Rav Aharon Kotler in 1943, in Lakewood, New Jersey. There was no time limit placed upon studying there, because its purpose was fundamentally different from all those kollels that preceded it. Its goal was to have the study of Torah being performed “for its own sake,” as per the innovative definition of Rabbi Chaim of Volozhin. This differed sharply from how the Rishonim defined Torah LiShmah. Furthermore, the students were specifically not to involve themselves with the local community, and not to be preparing for a role in the rabbinate or the wider community. But the wider community was expected to provide financial support for this and similar institutions, based upon the new concept of the innate value of the Torah study. All this in turn also required innovations regarding the halachic permissibility of such financial support, and of people not preparing themselves for an occupation; for while some precedent could be found in isolated opinions, it certainly went against the normative approach. The Hazon Ish is alleged to have invoke the emergency clause of “A time to act for God; overturn the Torah,” in light of the destruction of Torah Judaism in the Holocaust. This remained operational even after the number of Torah students vastly exceeded anything in pre-war Europe. The ultimate step in the evolution of the kollel, which spread in the latter part of the twentieth century, was its presentation as an expectation of every young man in the Haredi community. None of this was a resurrection of European tradition; it was an innovation.
 Adam S. Ferziger, “The Emergence of the Community Kollel: A New Model for Addressing Assimilation,” (Bar Ilan University 2006), pp. 16-19; Rabbi Nathan Kamenetzky, Making of a Godol, pp. 343-357.
 It is unclear, however, to what extent this was motivated by a desire to avoid Russian demands for rabbinic training in government-sponsored seminaries, and also to assist in fundraising purposes.
 This term was used by Rabbi Yaakov Kamenetzky, as cited in Making of a Godol p. 357.
 Yonsaon Rosenblum, Reb Yaakov, p. 90.
 See Norman Lamm, Torah LiShmah: Torah for Torah’s Sake in the Works of Rabbi Hayyim of Volozhin and his Contemporaries.
 See this post on "The Goal of Torah Study" and this post on "The Rishonim on Torah Study." See too this post on "Is the Kollel rooted in Yissacher/Zevulun?"