I guess it depends on what you consider "expensive" to be. It was about 1100 for all the new stuff (caveat is another 700 for a video card coming). I chose components that met my needs and were still at good "performance to budget" points. I did spend a bit more than necessary on the case, because this is a piece of desktop art and I wanted something a bit more flashy.
So if 1800 all in is expensive then yes (and I do not mean that to be dismissive or anything, We all have different views on what is expensive). In terms of custom PC's though it's fairly budget conscious. Just the parts for a full watercooling loop can run hundreds of dollars (USD), so I avoided that trap this time around. I also had not upgraded in 11 years, so I definitely got good value out of my last rig
I will 100% admit though, i REALLY want to build a Threadripper full water loop rig and wall mount it. My wife will kill me though if I drop 5 grand on another PC