Well, I can't speak as to the evolution of tarps over time. I've only been at this for the last year or so.
However, I can
speak to tarps as a means to stay dry dependent upon one's goals.
I came to this whole hammockry thing from bike touring. I'd gotten the bug to get out there and see northern Florida from the saddle. Part of that was camping; it was cheaper than staying in hotels...or so I thought, right up until the sticker shock hit...
As a part of that bike touring, weight was less of a concern for me than most hikers (FL is pretty flat, and the bike was carrying most of the weight). Bulk mattered, but weight was not as much of a concern. Also, I wanted a place where I could park the bike when it started coming down really hard. So, I got the free hex tarp upgrade that Hennessy sells with their Explorer UL model. It's an huge
tarp: 10' x 12'. It also weighs a pound and an half, which is on the heavy side for a backpacking tarp.
Fast forward a year, and I've gotten into the hiking thing as well. Well, hiking down here in FL is pretty easy. Aside from the heat and the prehistoric bugs, it's pretty easy terrain to hike through. Well, the mountains of SC aren't. Which pushed me towards the ultralight backpacking movement.
I've gone over to a DIY "postage-sized" asym tarp. However, as a part of my modular DIY hammock system, I've also got a poncho that doubles as an undercover/Garlington Taco. I've tested both in tropical storm weather (winds were only 20 MPH or so, but I stayed bone dry except for some water intrusion along the suspension) and am really happy with them. I don't think I'll be taking the tarp bike touring (I can afford the weight penalty down here), but it's definitely going to be my backpacking choice for the next little while.
So, form follows function. As always and alliterative.
Find out what works for you
. HYOH, as they say 'round these here parts.