Since we don't pay our Texas Legislators a "living" salary while they serve in office, the "common man" really can't afford to serve. Their salary is $7,200 per year, plus $128 per diem for each day the legislature is in session. That averages out to about $16K per year. Remember that unless you represent an Austin area district, you will also have to maintain a second residence in Austin during the session as well. You have to be in a job that you can essentially abandon every other year for about 6 months. Yes, the legislators do earn a nice retirement benefit, but again, the "common man" can't typically afford to defer those "earnings" if they are not drawing a paycheck now.
I'm not asking for change, I'm just justifying why it doesn't surprise me that Texas legislators have a fairly high level of education.
Every legislator I know either owns his/her own business, is a lawyer, or is financially independent.