It is, but it's more than just memory.
If you compare on cores alone (not saying that's how you should best compare two cards, but I'm not doing the math for every point):
RTX Pro 6000 Cost - (RTX Pro 6000 cores ÷ RTX Pro 5000 cores * RTX Pro 5000 cost)
U$8,565−(24,064÷14,080×4,569=7,808.84)...