White Wolf is in fact alive and well. They are currently publishing under the banner of Onyx Path Publishing, a company formed by White Wolf Creative Director Rich Thomas. They've simply moved from brick and mortar to digital and print-on-demand format. They've even been doing regular kickstarter campaigns for high-quality deluxe versions of their new releases. From the looks of it, all of them have been very successful.
Their FAQ explains that because of a decline in traditional printing, they've moved towards digital and print-on-demand formats instead. This is not only cheaper for them, but also has benefits for consumers, and for their development process due to the flexibility of digital publishing. With print runs, they would have to guess how well the book would sell, and order a large number of copies. Any left over would simply go to waste. A large-scale print run is a very in-depth process that requires many people to coordinate well in advance. That means that books could get released before they were ready, in order to meet printing deadlines. Digital publishing is much easier to postpone, if need be.
Digital publishing is also good for the consumer. With digital publishing, all of their books can be available to anyone who wants them. With large-scale print runs, once a book print run was ordered, that was it. It was rare to see additional runs. That meant that people who wanted to buy the book later on would have a hard time. With print-on-demand, they can keep their entire catalog available indefinitely.
This is also another benefit for them, because having a full library of titles in stock gives them a regular stream of income, rather than the one-time lump-sum income they would get from brick & mortar publishing. This also allows them to stay more financially stable in-between releases.