Yes and no. To be honest I did the same back-of-the-napkin math that you did prior to buying my MBP - the thing is the TCO is even worse if you customise the machine.
Example - a Mac is a Mac for resale purposes - if I attempt to later sell an XPS that I've opened up and put an SSD in and a couple of SODIMMS - I now need to recoup my cost on all of those things. The problem is that if someone is looking at a used XPS with upgraded SSD and upgraded RAM they're statistically unlikely to fully investigate and value the (probably really good) parts that you upgraded it with - they're just going to see X,Y,Z numbers and price accordingly.
Generally though, a 5 year old Windows laptop with 16GB RAM still commands the value of a 5 year old Windows laptop as best I could tell looking at resale values.
I wasn’t trying to address the resale value. Only the tax part. The perception of the tax comes from Apple simply not offering compromised parts for a particular set of parameters. And other manufacturers willing to sell at large discounts regularly!
Example - a Mac is a Mac for resale purposes - if I attempt to later sell an XPS that I've opened up and put an SSD in and a couple of SODIMMS - I now need to recoup my cost on all of those things. The problem is that if someone is looking at a used XPS with upgraded SSD and upgraded RAM they're statistically unlikely to fully investigate and value the (probably really good) parts that you upgraded it with - they're just going to see X,Y,Z numbers and price accordingly.
Generally though, a 5 year old Windows laptop with 16GB RAM still commands the value of a 5 year old Windows laptop as best I could tell looking at resale values.