How do all these aliens escape capture all the time?
Or that every government that has gotten an alien ship and crew has
managed to keep them hidden indefinitely?
Or why hasn't at least one of these apparently many species said to
heck with the Prime Directive and landed on the White House lawn to
say Hi or We Are Your New Masters or Have We Got a Deal for You!?
All these centuries of all kinds of reports and every one has managed
to elude real public revelation and solid, physical evidence. I know
humans aren't exactly the toughest creatures to delude and elude, but
what a track record!