1. I didn't say anything about starting salaries. I quoted average salaries. Don't twist words!
2. A school year typically lasts 180 days. So if you don't get two one-week breaks in February and April, you probably get more than two months off in the summer. Example, Miami schools start in mid-August but are out before Memorial Day because they only take a week in March. Cambridge (MA) schools start right after Labor Day and end in Mid-June because of a vacation in February and a vacation in April. The numbers are still the same.
(Year-round schools still keep the 180 day rule, as far as I know. They have lots of short breaks throughout the year.)
The school district may not pay you in the summer, but you're free to find other work during that time. Everyone choosing to teach knows this going in.
3. Sounds like a long day; the schools I looked at and most or all the public schools where I live run between 8 and 3 (most start later and end earlier).
But how much of that time are you actually teaching?