A team from Hong Kong visited Wuhan and the leader, a noted epidemiologist, said that this was "ten times worse than SARS". Since SARS infected a bit more than 8,000 people, that correlates with the leaked videos of Doctors saying that there are 90,000 cases. It's probably not even a case of the Red Chinese government intentionally lying: They're probably saying confirmed cases that have been subjected to RNA analysis of the virus are still less than 2,000; the other 90,000 cases or so everyone just knows has it, but they haven't been able to process test samples yet.
The videos of people collapsing and dying as they walk down the street and of bodies stacked in hospitals are quite disturbing however and suggest the government is lying about the death toll, and in fact, are generally much too complicated to fake, because they involve obviously the interiors of hospitals and large numbers of responding personnel and authentic Chinese-type ambulances.
The government is building another 1,000-bed SARS-type infection hospital in Wuhan (in only six days, the video of a hundred diggers working simultaneously on the site is rather impressive--prefabs, of course), and seizing hotels to convert into quarantine sites. More hospitals of this type can be built in other large cities and probably will be as the outbreak spreads.
Quarantine is effective, but only when it is at the home level. The government needs to promptly deploy troops to the streets of every city, place all the reserves under military order, and lock down the entire country. The disease would burn out if everyone remained in their homes for a month. The people in the infected homes would die and the rest would live. This is ultimately how we beat the Spanish Flu; ultimately, people just stopped leaving their homes and society isolated into small groups which weren't interchanging for long enough to break the cycle of disease progression.
Past modeling on a Coronavirus outbreak of this type has been done. The outbreak is dovetailing with the modeling nicely. It suggests 65 million deaths in one year, or about 0.8% of the world population. The Spanish Influenza killed 50 millions, but the world population was much lower at the time. However, it would definitely be the worst disease outbreak since then.
I would strongly disregard any claims of millions infected ... The 90,000 number is plausible at this stage, but not such wild claims off of radio shows.