I bought a pair of 2696v4 for $2k shipped, for a single 2696v4 build (which I tried for a few days before the arrival of the second cpu), the total cost would be -Each 2696 V4 on eBay is about $1169 used. That's 2338 for both processors not including motherboard and the rest of the components. So it's not the same price of a dual 2696 V4 considering that the 1950X is $999 at Microcenter and a dual 2696 V4 processor's cost $2338 for a pair or $1169 individually. So when you take into account motherboard and memory for a Threadripper setup it ends up being cheaper than a 2696 V4 dual-socket setup while offering better price/performance. Besides your comparing a single socket setup to a dual socket setup. That's not an accurate nor proper comparison.
$1k for 2696v4
$300 for dual socket mb
$1.5k for 16Gx8 2133p ECC REG SAMSUNG RAM
that is $2.8k for CPU+MB+RAM
for threadripper, you'd pay
$1k for processor
$400 for a x399 mb
$1.5k for 16Gx8 2400 RAM
the total is nothing really different, $2.8k or $2.9k in total.
you get similar Cinebench score for such two builds, around 3200 (assuming the 2400 RAM doesn't completely screw threadripper's performance).
different from the threadripper, which is pretty much a dead end, you can add another 2696v4 any time when you need more cpu cores, you can also install more RAM as there are 16 DIMM slots not just 8.