Equity is a weird thing. From the eyes of a businessperson trying to attract a developer, equity is very valuable. You don't want to give too much away and you want to vest it properly.
From the eyes of a developer, equity is not very valuable. Equity is a chance at money in the future, not money today. Vested equity then feels more like a chance at a chance of earning money in the future. And most startups don't ever make money. If you're a developer worth his/her salt, you can make really good cash right now at a typical job or working as a consultant.
One thing I've learned is that I'd rather be a developer than a businessperson. I realize that I have the opportunity to run a single founder, bootstrapped startup if I wanted. If I were a businessperson, I wouldn't have this option. If I had a product idea I would have to attract a developer and/or investment money first. As a developer, if I have a product idea I can just launch it and see what the market does and worry about investment, attracting another partner, etc. later.