Sadly true. One scientist said it would take months or weeks, not hours or a day, to intercept and interfere with such a hit. Such as bump it off course. We don't even have the serious beginnings of a force to react.
The big brains are "studying" and "learning from" the near misses. They haven't even mapped and tracked many objects so far. Each year they add to the database. Many are a total surprise to the "experts."
Worse. One documentary said the consensus is for the mathematical chances of a very large object hitting the earth within 20 years are effectively 100%.
Hold on here folks. 0.05 AU ~=4.5 million miles. Not quite what I’d call a near miss.
My 2¢.
Ed