MYOG is great. Satisfying, just what you want, a learning experience, money-saving, etc.
But buying gear is great, too. What I'd urge you to think about is 1) the cost of basic materials and 2) the amount of time you'd think it would take to make a particular item well. For 1, if you want the absolute lightest or close to it, the materials are expensive. The type of development and machinery it takes to produce fabrics like spinnaker and cuben are complicated and the market isn't huge, so there's really no way around that for small business owners. For 2, if materials cost you $60 for a bivy sack that costs more like $175 from one of our belovéd cottage manufacturers, $115 of that is for time. How long does it take to make? If it took 8 hours, that'd be $14.38 an hour. At that rate, the manufacturer would be making $575/week, $28750/yr with two weeks off. I understand that with outfits involving more than one person, added costs, website maintenance and bandwidth, customer support, tools, tax, etc., that it becomes much more complicated. But, at any rate, I'd guess that my estimate is higher than what's actually made by someone in the business. Personally, I am more than happy to pay for UL gear that is much better made and developed than something I'd make at home, supports manufacture in the USA, and supports wonderful individuals who have the guts to start their own business and support this community.