Steel is the foundation of worldwide industry because it is readily available, easy to work with and cheap. It is very rarely the ‘best’ material for the job but it is often the most cost effective. If people could afford to build ships from titanium they would because it doesn’t rust for example.
You really don’t think carbon hasn’t progressed from the days of chopped strands and hand layed up polyester resins? The bare material is still essentially the same i.e. carbon, but resin and manufacturing technology has advanced massively. You could just as easily argue that ‘high tech’ steel is still essentially iron.
The major use of titanium is as a pigment in paint, there is very little used in a set of golf clubs. Far more steel, carbon and rubber are used than titanium, which is only really used on the face of ‘woods’.
Back to the OP, I think the same as Ben, titanium is usefull in soft-tail situations where the chainstays flex to provide a bit of travel (like the Moots). As a regular full-suss design carbon and ali would seem to be better options, although the Eriksen above looks really nice.