This is because Apple recently added an 8TB SSD storage option. This upgrade would cost customers an additional $2,600. Prior to this, the max storage size that users could opt for was 4TB which would cost customers an additional $1,400, so it looks like if you decide to go for 8GB, you’ll be paying an extra $1,200, bringing the total price of a maxed out Mac Pro to around $54,000.
That being said, we should point out that things could get potentially even more expensive as Apple had previously stated that there are plans to add options for the AMD Radeon Pro W5700X GPU and dual Radeon Pro W5700X GPUs, meaning that the total price should go up even further in the future.
No word on when those options are coming in, but the good news is that the Mac Pro is a modular computer, so upgrading it should be a relatively easy process in the future should you ever decide to do that.