I am not sure your premise is valid. You likely would get a fuller answer on r/technology, but titanium is used in many places in aerospace. It is used very often as a hard coating, titanium nitride, on cutting tools. It can be found in super-lightweight cookware for backpacking, or for high-end tennis rackets. It is readily adopted by surrounding bone, and so is used for artificial knees, elbows, and other replacement human joints. It's resistant to lots of acids and chemicals, and because it's very strong it can be used for boilers and condensers in nuclear reactors.

But it takes a lot of energy to refine the stuff from ore. Titanium also has exotic properties. Many quirks were discovered after the initial surge of enthusiasm in the 1960's. It was found that it combines readily not only with nitrogen but hydrogen as well, and both can make it brittle. Hydrogen embrittlement was found to be a consideration during fabrication and machining- and most machining coolants use dihydrogen oxide, or water! Heat treating also therefore has to be done in a vacuum...and, when you think about it, transferring heat in a vacuum, with no convection possible, is kind of hard.

To get a bit of an idea of how tricky it is to work, here's a quote from Production Machining

Titanium is an extremely potent solvent. It forms very stable bonds with oxygen, nitrogen and carbon. That means, given the right environment, titanium will rapidly degrade any areas of a cutting tool that are in contact with it that contain oxides, nitrides or carbides. All of these are elements of carbide cutting tool coatings and substrates. In addition, titanium’s thermal conductivity is famously low among metals. It is so low that most of the heat generated in the primary shear zone as a result of chip formation remains in the chip. The heat is then transferred to the cutting tool through the amount of contact area between the chip and the tool. Another consequence of the low thermal conductivity is that almost none of the heat that is otherwise quite useful in metal cutting is propagated ahead of the cut. In other words, none of the typical benefits (plasticization, local reduction in yield strength, lower cutting forces and reduced wear) are realized, while all of the disadvantages (softening of the cutting tool and reduced energy barrier for chemical reactions) are experienced. Finally, titanium is very ductile and goes through a large region of elastic and plastic deformation before finally fracturing to form a chip. Once the fracture starts, elastic deformation is recovered and the deformed layer springs back, resulting in a great degree of variation in cutting forces per revolution — even in continuous cuts. Mechanically, machining titanium is likened to machining a wet sponge. Using cutting speed parameters that current tools and machining environments allow, the chip formation is cyclical and produces a segmented, serrated chip, which tends to exacerbate the mechanical abrasion of the tool.

So, it's not that it's disappeared: it has just been found to be very expensive to refine, machine and fabricate, and that limits what can be done with it.