Palo Alto: Averages roughly $4,000,000.
http://www.zillow.com/homes/for_sale/Palo-Alto-CA/fsba,fsbo_...
Austin, Texas: Averages roughly $400,000 (10x less)
http://www.zillow.com/homes/for_sale/Austin-TX/fsba,fsbo_lt/...
Orlando, Florida: Averages roughly $400,000 (10x less)
http://www.zillow.com/homes/for_sale/Orlando-FL/fsba,fsbo_lt...
Chicago, Illinois: Averages roughly $800,000 (5x less)
http://www.zillow.com/homes/for_sale/Chicago-IL/fsba,fsbo_lt...
Philadelphia, Pennsylvania: Averages roughly $400,000 (10x less)
http://www.zillow.com/homes/for_sale/Philadelphia-PA/fsba,fs...
Seattle, Washington: Averages roughly $1,000,000 (4x less)
http://www.zillow.com/homes/for_sale/Seattle-WA/fsba,fsbo_lt...
Palo Alto is definitely _much_ more expensive.
So make that a factor of 30, without even looking at bad places.
Glassdoor says that Harris pays $113,051 for a "Software Engineer IV". Most Harris jobs are in that area.
Payscale says $96,955 for a "Senior Software Engineer" in Melbourne, the next town over. Hmmm, Palo Alto is only $135,305 for this. That's less than 40% extra, but you're paying 3000% extra for the house.
Note that overtime is not normal for the area. You work 40 hours. Spend the rest of the time with your family.
Also note that everything else is cheaper too. There is no state income tax. The sales tax is 6.5%. Power is about $96 per month for those using 1000 kWh per month, and $137 for those using 1400 kWh per month. You'd pay 20% more in Palo Alto. Gasoline is dirt cheap: it's only $2.14 in Palm Bay, but about $3.05 (large variation) in Palo Alto. I could go on forever really, but it gets silly comparing everything from nail polish to turnips.
And yes, we have a tech industry.
Saying that middle class in PA starts at $250K sounds about right. It is very difficult to have a family in the area for less than that.
Source: I recently moved from Mountain View to the Midwest (family of 4). My wife and I have talked a lot about moving back, but we decided that a minimum salary level would likely need to be above $250K for us to even consider it.