Nobody has the time to grow a relationship....
I hear all about how relationships require a "spark," but I'm here to say, it's bullshit (and I should know, because I've been through many relationships over the past 15 years and I'm pretty damned sick of them.... and at 59, I'm going to give it up in, say, 20 more years...)
This whole thing about "sparks" is kinda bullshitty and reflects the kind of impatience that has developed, probably part of the internet dating age, where there's another person just a click away. From what I can tell (from my neighbors, who have been married over 40 years), strong relationships come not from "sparks," but from "embers." That is, there is an interest, and that interest grows with time... and I mean intellectually, emotionally, sexually.
But as one date told me, she doesn't have the time to invest in someone who doesn't spark her immediately. Of course, she hasn't had a relationship in over 10 years, because she rarely goes on second dates (and because her dates feel the same way.)
So what happens when nobody takes the risk and tries a second date with someone who doesn't "spark" them immediately? I guess it's an endless number of "first dates."