The material of diapers changed from heavy weight knit to lighter non-woven fabric. Non-woven loops have a much shorter fiber available for engagement, which requires the hook product to reduce in size and shape to engage.
The evolution has led to YKK SureFit® hook fastener, which is designed to engage with fibers from all 360 degrees angles. The tip of the hook dome has a claw-like design that holds to these shorter fibers once engaged.