The answer to those questions is fairly simple, Acts says that people were drawn by the signs which the apostles performed, hearings, et cetera. But more importantly, they were drawn by preaching, by the faith of the Christians and by their love for one another. The state of Catholic preaching today seems to have attracted considerable criticism even by the preachers themselves. People are expecting more in their Sunday homilies than they once did. And that is good.
Catholics are also much more mobile today than in former times.
If the preaching in their local church does not inspire them, they drive across town to a church where their hopes are better realized. One would think, of course, that this would stimulate the efforts of the preachers, and often it does, which is good. So, preaching generally is getting better. I imagine any one of these might attract some people, but my hunch is that there needs to be something deeper and more substantial to attract people to an authentic worship community. It is hard to define, but folks know when it is present and when it is not present.