Indeed. The material itself wasn't that expensive, but there was a poor selection of suitable sized, suitable quality titanium tubes for chain and seatstays, and a lack of the skills and equipment to shape them to clear the fatter tyres and triple chainsets - requiring a costly investment in manufacturing processes, even if you could already weld titanium alloys adequately.
Remember those stories about Russian fuel pipes?
Quite a few early ti frames were too flexible, and this probably led to a higher than acceptable fatigue failure at the welds.
Now steel we'd already been building double triangle frames with for 100 years by 1986. Most problems had been ironed out, tube selection and fabrication skills were abundant.