That being said, I don’t completely discount the possibility. One answer to the Fermi paradox is that there isn’t one, and I can think of many reasons multiple governments would try to keep stuff like this secret.
Aliens have super sophisticated tech that is hardy enough to travel millions of light years through space but it crashes so easy on earth? What caused them to crash?
I'd like to believe, and I think 1 or 2 might be reasonable but the claim is 12, which doesn't account for ships obtained by other nations as Grusch said I'd happening.
I still believe it's possible, and hope it is, however something feels staged about this, maybe to get more money for certain agencies, or some other motive.
Selection bias. We don't know how many crafts fail to make it to Earth. Maybe the trip is extremely dangerous and only a percentage actually make it.
And/or, like most air & space travel, takeoff and landing are the most dangerous parts.
Also, we have a very good handle on air travel, but planes still crash sometimes.
(I don't actually believe we have ET crafts coming to earth, but it's fun thinking it through).
(1) The probes, like ours, are not designed to return and have a limited life span. Maybe they just gather and transmit data until their power source runs out or something on them breaks and they crash.
(2) Maybe there are thousands of probes or even more (even from multiple sources!) and only a small percentage of them crash. Of course one would assume we'd be seeing them more often if this were true.
(3) We shot them down. That's not impossible, especially if they are just probes and were not designed to deal with something intelligent intentionally flinging high velocity chunks of metal at them.
The last could easily occur if we mistook them for e.g. Soviet/Russian or Chinese surveillance craft and they repeatedly refused to respond to orders to withdraw.
Why would someone send probes here? This planet has been broadcasting "possible biosphere right here!" for at least hundreds of millions of years to anyone capable of doing spectroscopy on the light it reflects. You wouldn't be able to see detail from another star but you could determine things like atmospheric makeup and conclude that there is very likely to be something interesting here. You'd see a ton of oxygen (which is hard to explain abiotically), water vapor, traces of hydrocarbons, and possibly evidence of sunlight being captured by something complex (photosynthesis) vs just reflecting off rocks or ice. Lastly the planet has a large moon and is not tide locked to its star, both characteristics that increase the odds of something complex evolving here (as far as we know).
Multiple different sets of aliens, fighting over Earth. (I’m not saying that this is true, just that it is one scenario that explains crashes happening if there were aliens as described building craft capable of visiting Earth.)
Because nobody has figured out an autopilot that doesn't shit the bed once in a while? I'm betting on taking a nap in the backseat is just a universally bad idea when nobody is driving.