They say to expect a Tunguska sized one once a century and this one wasn't that big. They mostly ocean explode or strike so there's few signs of them but an ocean strike can be worse than a land one given the water they displace. They've got to wake up and start properly funding the near Earth program. It still won't protect against rouges but at least they can map ones that cross our orbit.
Just detecting these things can cost billions. Doing anything about them can cost trillions.
And most of these are air-burst, like yesterday's, (and like Tunguska). Since statistically, 3/4 of all are likely to hit ocean, the return on investment is going to be un-measurably small.
Air bursts over water are not likely to generate any significant amount of water displacement, and therefore no ocean wave damage.
In fact, if you take the Tunguska event, you learn from wiki "To the explorers' surprise, no crater was to be found. There was instead around ground zero a vast zone (8 kilometres [5.0 mi] across) of trees scorched and devoid of branches, but standing upright.". A similar event over water might generate some local surface waves, but nothing of significance because there would be nothing offering any resistance to the blast wave.
Take something the size of the object that created Meteor Crater (50 meters in diameter), about 3 1/2 times as big as yesterday's object, didn't air-burst, but a substantial portion of it burned up on entry. The crater (3/4 miles in diameter) could have killed at most several million people if it hit down town London or New York city. But the biggest cities on earth are a tiny target.
But its likely it would have never been spotted, not by any technology today, and not by any technology proposed. I suspect the cost of developing the technology and maintaining it year in and year out, upgrading it every so often, shutting it down in periods of austerity, firing it back up when fears are rekindled are simply not worth the effort, especially when you consider the chance of success is minuscule at best. Its most beneficial effect would be as a jobs program, for people who believe the government should be the source of all jobs.