Why does ad targeting still suck?

We've been in the US for a week now. Every year, we spend three months with my in-laws in Texas. It allows me to travel the country, spending time on both coasts and some beautiful places in-between (Austin, Boulder, and maybe a wild card this time... Raleigh?). 

The spare car that we had been using in Texas had flooded during Hurricane Harvey. So I did a few minutes of research on the startups that would allow me to avoid the American dealership "experience" and (sorry, Elon) decided on Carvana.  

It was a good, nay, a great choice - within 24 hours of arriving, the car had been delivered to the house, paperwork signed, and we were adulting Texas style in a seven-seater Chrysler Pacifica. Yes, it's a minivan. It was that or a Ford Raptor and my wife x-nayed that idea. 

So imagine my surprise as I was reading Amazon Pravda Essentials (about Robert Kagan's new book, which is the talk of the town in DC, except of course for that other pesky issue of whether you-know-who likes beer and how much of it), when this popped up:

That's a retargeting ad for Carvana. The place where I just bought a car and took delivery. Do they think I might want another car? Maybe because I had used the prior one up? Monthly subscription? Get the next one half price!

Criteo was founded in 2005. Given all the data that Facebook and Google have on me, given all the ways you can close the loop on this transaction, what is going on?

Amazon does this, too. Amazon, where I do like 200 transactions a year (seriously, this is a problem), cannot tell that I have just bought a garden hose and am highly unlikely to require another one for the next five years. 

In a way, that's fine. It's giving me some peace on the big data (do we still say that?) issue that we're so god-awful at using it. Now we just need some legislation on what that data can't be used for (health insurance, credit scoring, immigration) and we're solid. 

In the meantime, let's hit some open road.