They've also said that their high false negative rate is why they clear out their records every couple of years. If you got rejected a couple years ago you can apply again and they won't be looking at your previous attempt's performance.
It kind of goes against Google's entire corporate culture to ever delete information like this. Sometimes I wondered if their interview process isn't designed more as a data mining process to find out what interesting things technology leaders are working on.
What Google should do if they want to hire really good candidates is to go with a contract to hire approach. Find good candidates, do one phone interview and a second in-person interview in the space of a few days (not 4 or 5, stretched out over months). If they pass your initial 2 interviews, hire them as a 6 month contractor.
See how much they accomplish in 6 months. If they are contributing and integrating effectively, hire them full time. If not, just wish them the best and don't renew their contract.
This is the way it works in most effective large companies. The cream that rises to the top gets offered a full time job within a 6 month to 2 year timeframe. My current job is like that. I've worked there for 4 years and started as a contractor. It became so expensive to pay my hourly rate that they were begging me to become full time after a while. I was doing a valuable job for them and was very effective at it, so I got the full time offer.