For the record, I didn't make the "6 digit salaries" claim. I'd be thrilled if world-class (or even top 5-10%) teachers could command those kinds of rates without having to teach in the richest school districts for decades.

I'd also note that those are salaries (and similar for others in this discussion) are for 187-day school calendars, or 37.4 weeks/year. Generously applying the same rate to a 46 week/year "full time" calendar puts the top end in Round Rock at over $78,000. The median household income in Round Rock is around $70,000[1], suggesting that it isn't outrageous for a couple of married teachers there to earn well above average, even without summer income.

Also, at least in MA, many teachers are not required to pay Social Security tax, but instead pay into a much more generous pension system. Other benefits are also competitive relative to the private sector.

Again, though, I'm all for teachers making more money so more talented people are encouraged to teach. But the tenure system is not the way to get that result.

[1] http://quickfacts.census.gov/qfd/states/48/4863500.html