Fierce competition led to aggressive innovation and a race to slash prices and improve quality. The government took a long time to realize the pace of these developments, and was slow in hampering the growth of what we can assume is still the freest sector of the Romanian economy. That the number of ISPs has dipped in recent years may indicate that the regulators are catching up, but the market seems to be going strong for now.
the tl;dr is that because of limited government regulation in Romania, many new ISPs were able to enter the market and compete for market share. that resulted in lower costs and higher quality for the consumer. the only thing slowing it down now is more government regulation, but it's still a strong market. you can get very solid internet for much less than what it costs in America.
poor Bernie probably thought that Romanian communism from decades ago had something to do with it, though. America needs to make it easier for new competition to enter the market. it's the only way for competition to drive down prices and increase innovation. right now the government is propping up giant mega-companies like comcast and at&t and the like, and these companies are so powerful and so ironclad because of the protections afforded to them...that no new ISP has a chance at growing.