Among the legacy of the Progressive Era is the 17th Amendment to the Constitution which provides for direct election of Senators. Senators were previously elected by State legislators. Additionally, the referendum, initiative and recall, still practiced in many states, was the result of Progressive policies. The abolition of child labor and the eight hour work day as well as laws protecting women from hazardous occupations also resulted from Progressive Era reforms. The by-word of the Progressives was that the cure for the ills of democracy is more democracy. They demonstrated this in the ways I have set forth above.
I'm not sure that government regulation of business arose from the Progressive era, other than Theodore Roosevelt's campaign to break up business trusts (which were obviously abusive) and regulation of the meat industry after his reading of The Jungle.
I would argue that the Progressive Era set us on the road (for good or for ill) to the society in which we now live. This is a society in which the government tries to regulate our economic actions to a large extent and in which it tries to improve people (for lact of a better word). This all comes from the Progressive Era.
The Progressive Era was the start of the government's intervention in the economy. It was then that trustbusting started as did things like clean food and drug laws. These have multiplied in the time since and we now have all sorts of regulations to protect us from what businesses might do to us.
The Progressive Era was a time of government intervention in people's personal lives. The major example of this is Prohibition. Now, we have all sorts of laws to improve us, whether we want to be improved or not. We have laws telling us to wear our seatbelts. We have laws banning (in only a few places) transfats. We have the government spending lots of money to try to stop us from smoking.
All of these types of government intervention come to us from the Progressive Era.