Rav Shach  thought that the kind of Lithuanian yeshivas that were built on the European model were the  sole source of Torah in this generation.And in particular he mentioned the idea that learning Talmud together with Musar was the sole means for Torah to continue. There is a lot to be said for this. But mainly we can see that his intention was that people should learn Torah whatever way that would be possible. And for people beyond the age of yeshiva [18-24] there is not much choice but to learn Torah at home.
 But it is probable that Rav Shach was thinking of the idea of kollels. In Israel I was a part of this system and it is basically geared so that people can learn Torah their whole lives--and it is supported by the State of Israel. In NY this kollel system I think is supported by the State of NY but I am not sure. It might be from the Federal government.--I never asked. The wife of Shmuel Berenbaum was in the office all day long taking care of the business matters of the yeshiva while her husband did the learning and teaching. All the people in the kollel, including myself, just simply were handed a check every month by Rav Handlesman [or his son] who was her assistant.

In any case, the major idea of Rav Shach was that learning Torah is a requirement for every person from young to old, sick or healthy, etc. and no one is exempt.
This idea I have found is almost impossible to relay to people. And whenever I have tried to express this idea to people I have encountered a lot of resistance.

But the fact is it is this idea of Torah being an obligation on everyone which forms the basis of the idea of Rav Shach that since most people are not learning Torah as much as they ought, therefore the only place where the Torah is found is in Lithuanian yeshivas where at least the ideal is nurtured.

Now the idea that Torah is important you can find in a statement of the Gra

But for right now I want to quote the Gra: "Everything that was, is, and will be is all contained in the Torah from "In the beginning God created.. until in the eyes of all Israel," [the Five Books of Moses]- not just the generalities, but the specifics of every species, and every single person and everything that happened to him from the day he was born until his last breath and everything in between, and also every living creature,--everything that will happen to each one individually. Everything that is said about the Patriarchs and Moses is in every generation. For they and their sparks are in every generation. And all of that is  contained in the first section of the Torah from Genesis until the story of Noah. And also in the first chapter of Genesis. And in the first seven words of the Torah--from the beginning until the end of time."

The letters of the Torah are the life force of everything that exists. On the face of it this idea looks different but you can see that since the Torah is the source of all life and being then it all must be contained in the Torah.
 it is possible to find Torah everywhere and in everything. but the letters of Torah are not always shining. The lights might be turned off. To find the light of God and Torah in things requires a kind of merit. It is not by knowing by means of kabalah what letters are in things. It requires a kind of sexual purity in order for the letters to shine.

I tend to agree with Rav Shach and his was the general yeshiva approach in those days.  The basic idea of Rav Shach is that in every waking moment everyone should be learning Torah except for the time needed to be making  a living. And it is agreed in this approach that Torah is not to be used to make money. And that makes the kollel thing awkward.   In any case the idea of kollel is that they  receive money in order to learn, not learning to receive money. That is at least the theory behind the whole thing. In practice things have evolved so that kollel becomes  a way to make money.

In any case, in this approach it is hard to find time for other areas of value. One can in theory claim he is finding letters of the Torah in other activities when that might be just an excuse. So the great yeshivas in Israel I still think are worthy of support. I can even name a few for those who are interested. Ponovitch, Mercaz HaRav of Rav Cook, Tifrach [I have heard tremendous praises but I have not seen the place, and Rav Montag's Kollel in Netivot which seems more like a full fledged yeshiva rather than a kollel, and Rav Zilverman's Aderet Eliyahu in the Old City of Jerusalem. All these places I think are worthy of support.--though again I have never seen Tifrach but from what I have heard it is off the map.]