I think it's a matter of people (especially those who don't ride, or don't ride much) not knowing what the difference is between a Wal-mart Schwinn and...basically anything else. If you only ride a few times a year and it's just around the local park or something, then you don't need anything more than a $200 bike, and while you know that the pros ride a lot and need expensive bikes, you really don't understand why anyone who isn't a pro would possibly need anything more than the aforemention Walmart Schwinn. (I used to work at a bike shop. I heard this sort of thing a lot. The same people also thought that riding 20 miles was crazy.) It is true that a nice, light, spendy bike by itself won't make you faster, but it certainly makes your ride more enjoyable, and a lot of people don't ride far/often enough to actually appreciate the difference. If you ride hundreds or thousands of miles a year, yes, you do get the difference! They also may not understand the componentry/frame material properties--it's not all weight savings, but again, if you're not riding much, you won't know this.

As for clothes/TV/technology...whatever. Each to their own. Hobbies of any sort can be really cheap, or really expensive. (There are knitters out there who will spend $50+ on yarn for small garments like socks and cowls. As pretty as the yarn is, I cannot fathom spending that much.) If you enjoy your bike or TV or fancy handbag, more power to you.