I can't see anyone buying a 3600 class chip for £250. That's bonkers.
If the 12 core 3900XT is worth £499 there is an argument that a chip with exactly half the cores and power is worth £249...
Now due to the laws of diminishing returns the argument is probably invalid (the 3700x will give you 60-70% of the power for £270 say) but it is an argument..
And these processors are really there as flagship holding points until the 4000 series arrive later this year.