"Don’t buy (an) expensive Tarp/Quilt; save your money and put it toward (a) good sewing machine.”
That's a time/money thing.
Working full time and making a decent salary, I'd rather not spend my evenings and weekends learning to sew.
In the long term it is perhaps less $$$$. But how many hours would I need to learn how to sew a decent pack or shelter?
One answer is not better than another, but sometimes the cost of time is more than the cost of money for some people.
I have swap out car batteries because it is quite easy to do so and not worth getting a tow/having a mechanic place in said battery.
OTOH, I don't have the right tools or space to say change the breaks on my car. If I could figure it out (and, I probably could) it would probably take more of the precious time that I have relatively little of.
Having the luxury, I choose to spend a little more of my money so I have more of my time.
Nick G has a good post for this:
http://popupbackpacker.com/managing-your-recreation-inventory/
There is no right answer. I truly mean that. But for me. I'd rather pay $100 for a pack that is pretty good and light and meets most of my needs vs getting a sewing machine and putting the hours in to learn how to make my own pack correctly. Others love to make their own gear, get everything just right and have fun doing this hobby. And that's cool.
I appreciate the value of something made by hand. I think I'm a pretty good cook for example and really don't enjoy going out to eat to most restaurants (brew pubs and family run ethnic restaurants are another story!) Other people look at me spending hours making a lasagna and said they'd rather buy some at a restaurant. All different values depending on your needs.