I think there's no good one answer that fits everybody equally
people do cast wider nets because tailoring individual messages to every single person they reach out to doesn't have the same rate of yield
just because you do spend time on someone isn't a guarantee that they will necessarily respond in the way you want
doing a mix of both isn't necessarily the answer either
And what does effort really mean? Does it mean responding right away (or within like 10-20 minutes)? Does it mean coming up with interesting things to talk about? Does it mean saying the right thing at the right time? All of them at once? Or just being yourself, which could mean literally anything?
Different women like different things, so to say "effort" is needed isn't specific enough to tailor to those specific women–after all, how are you going to know what someone likes before you get to know them?
Dating is hard, and the more people you meet, the harder it is IMO
A part of me wants to say it's easier to be sad about 1 person than 10, but it also depends on who that 1 person is vs that 10.
Did you tailor your messages to that one perfect, handsome stranger and fail? Or did you send a bunch of half assed messages to a bunch of people you just wouldn't mind getting to know?