Why has there been a lack of scientific research findings on the golf swing?
1. Most teaching pros think that they know it all already. I'll bet that not 10% of PGA Members who teach could pass a 100 question test on the basics of the bio-mechanics of the golf swing and physics of the impact collision, prepared from such must-read classics as "Search For The Perfect Swing" and "The Physics of Golf".
2. The PGA of America would rather spend its money on "grow the game" initiatives, that don't work, than something worthwhile, like research funding, which could, in the end, make the members better teachers, which actually would grow the game, by helping people to play better, not worse.
3. The OEM's are in the business of selling clubs. In this competitive environment, R&D is usually top secret.
4. Scientists do research. That's what they do. When studies have been done on the golf swing, often it is just for the sake of research. They are not interested in profiting or ramming their findings down some arrogant know-it-all teaching pro's throat. But thankfully, they will share.
We are long overdue for a new book with updated research findings on the golf swing and impact collision. Project 1.68 sounds hopeful.