Why do cops use technology only to make money, why not use technology to stop crime where they can?

Technology costs money and traffic fines generate money. Plain and simple. The advancements in law enforcement technology isn't all directed to traffic enforcement. How much do you think it cost to develop and maintain the DNA labs and standards used by Cops today? How much does all the wireless technology used in law enforcement today cost? Do you even have any idea about the vast amount of surveillance equipment available to law enforcement today, or it's costs?