Currently in the United States of America, we have the means of protecting ourselves. I don't believe security systems are effective, but firearms certainly are. However I don't know how long that will last with the upcoming gun restrictions. I suggest we keep to our guns and protect our homes.
Yes, we do enough to prevent invasions of homes. There are so many different security systems these days, and many of them are affordable. Furthermore, many families have weapons in their homes for extra protection. Some inventors have even created the SALT gun, a non-lethal approach to home invasion that uses paintball-like methods to incapacitate invaders. There are definitely enough ways for us to protect our homes; it's just a matter of implementing them and teaching others how to defend ourselves.
I certainly don't want someone else telling me I have to increase my home security to "prevent" a home invasion. Bad enough the nanny state mandates seat belts. If I want to prevent my home from being invaded, I can get a big dog or a small gun and post an appropriate warning. Home invasions are a symptom of a society that is disregarding its rules, and having some "we" trying to "prevent" them is only a band-aid on the problem.
Yes, the states do as much as possible to prevent home invasions. Home invasion burglaries are treated seriously by the states through their individual criminal statutes, carrying the potential for long prison sentences and other stiff penalties. While the law can approach home invasions with punishment after the fact, it's up to individual homeowners to make certain they have adequate security features installed on their homes.
The average person does not do enough to secure their home from invasion. The vast majority of homes can be entered quite easily by a determined invader. To expect laws to do this is irrational. To invade someone's home is illegal, so anyone who does so is obviously not deterred by laws. Although law enforcement will respond to a report of invasion, this is by definition after the fact and not a preventative measure. There are ways to greatly improve the security of one's home and many do not require large investments of money. A simple way to do so is to systematically break into your own home and then secure the home against each method that works.