It depends on the station. Once again, radio is not one thing. It's thousands of stations and hundreds of owners.
The transition will not be one-for-one. Ad rates for online are much lower, and you can't do the number of impressions the advertisers want if you're not a linear service. So they will NOT sustain current revenue levels. They HAVE to diversify. Look at the music industry as an example. The labels made more money when they were selling physical product. They had to take a haircut when distribution went digital. That is simply the reality we all have to face with digital. The only people making money in the digital world are ISPs and tech companies.
So yes, the layoffs will continue until radio companies are staffed differently, and build on user-generated content like this message board rather than paying staff with salaries and benefits.