One reason is payout vs. payback. Up-front cost is real, while return on investment is speculative. Another reason may be inadequate knowledge. People with decision-making power are not necessarily expert in statistics, automation or production. Maybe they're suspicious, disappointed by earlier strategies and technologies that fell short of expectations.
Some people simply resist change.
Well, here's why. Nearly 70 percent of part defects originate in design. About 30 percent of defects remain subject to production process control. If world-class quality is your objective, you must become able to detect inherent flaws and to control the process. Because quality begins with design and flows all the way through to shipment, it is necessary to involve people at many levels.