Why are so many people spending so much money to build “perfect” streaming system?

Get a bluesound node. Easy to set up and use, good sound, and not at all expensive. Once you actually start to stream, you’ll get why all the fuss. From there you can decide if you want to spend big bucks to upgrade. And if not for some reason, you can sell it and make back most of your money. 
An analogy - taking up golf or tennis, you buy in cheap, go to a public course,  if you like it playing, you upgrade, if not, no big loss.

Another point, are you still listening to 78 records or have you upgraded to 33 1/3? Also, there’s these new things called CD’s that I hear sound better then records. You do have to buy new equipment. Streaming is just a new way to listen and the cost can be very a reasonable few hundred dollars. Or you can spend $10K on up, it’s really up to you.