The problem is that ruins are there and stay there. UFOs (whatever they are) appear irregularly, don't stay for long and aren't amenable to being picked up and put in a lab. What do you study, other than location and time of sightings?
Even if there funds available for a complete survey team (or teams) with cinetheodolites, multiple camera systems and whatever other instruments you want, how do you deploy them? Stay in one place and hope, or chase the things round the world only to turn up after they've gone?
I agree it's facsinating. And I agree that most reports say some some sightings cannot be explained, but the problem is having equipment THERE and THEN when they occur.
There very well maybe something worth studying but it's so bloody unpredictable and transient that at the moment it would cost more than it's worth... sad but true.