Could you explain why any of the things he says make you think a number that high? I'm just finishing building my first PC ever (I've used computers for ... 20

Could you explain why any of the things he says make you think a number that high? I'm just finishing building my first PC ever (I've used computers for ... 20 years? But never actually built one). And I have a 1TB NVMe SSD from Western Digital, it was about 60 bucks. I have a 35" BenQ monitor from work, I think it was around $600 at the time of purchase. I don't have fiber at my home, but from what I understand, it's not prohibitively expensive in general. Anyway - I went with 16gb RAM. That felt like a reasonable starting point considering my current and prior daily driver were there as well. My build (minus admittedly expensive monitor) was, to me compared to the Macbooks I usually have for work, a fairly modest $1250 or so. So, roughly the same specs - seems like nothing too crazy?