It's great you were able to pay cash for your college education, but unfortunately, times have changed. I just finished my 4 year degree and now owe student loans to the tune of some $43,000 + for my Bachelor's degree. Too bad my boss won't give me an automatic $300 + month raise to offset that new payment!
Your idea of real estate investment may work well for you, but that same plan may not work well for others. I know first hand the problems you can run into with home purchases, upkeep, upgrades, etc. If you or your spouse can do those repairs and keep the costs down, it is a huge plus - if not and you have to hire them done - the expenses may simply outweigh the income on any rental property.
Good luck!