If you think Lufthansa is bad (they only use two titles plus address—or three titles if you include Mr/Mrs as a title), then wait till you see British Airway’s list:
On the other hand, Finnair does precisely what you suggest:
Given this glaring difference between three European airlines (and flag carriers) that should otherwise be very similar, I strongly suspect the underlying reason is one of culture, heritage and history.
In Germany, the title Dr. has a special legal status, can be added to your ID documents, your credit card and you can insist on being called Dr. Meyer. Prof. does not have this special legal status but still carries a general prestige with it; interviewees, for example on television, will often be titled Prof. in the name badge things that pop up at the bottom of the screen if appropriate (exceptions exist).
In the UK, aside from the old distinction Mrs/Miss still being kept (as well as the more neutral Ms being available) and the you’re-not-quite-a-Mr-yet,-boy title master, a lot of those titles that can be selected relate to the old aristocracy or still existing royal institutions (The Rt Hon). While indeed most of the time most of those titles would not be used, proper politeness in formal situations requires being aware of them.
In Finland, society is perceived as much more egalitarian. Thus, all those distinctions are irrelevant and it boils down to Mr/Mrs (although the selection fields are male/female).
To further elaborate, allow me to present the booking form of Deutsche Bahn, the German railway company where online tickets are tied to a specific person whose name must be entered. I couldn’t expand both menus simultaneously, the left one simply contains the options Herr and Frau or Mr and Mrs. In a sense, it is identical to Lufthansa’s except it separates the gender and title into 2 × 4 fields rather than one list of 8. (I didn’t think of using the English booking system, sorry.)