It's hard to say.  There's been speculation Mueller toned it down in the fall because of the mid-terms.  It could also be the mid-terms crowded out Mueller and they have column inches and air time to fill.

She believed in nothing; only her skepticism kept her from being an atheist. -- Jean-Paul Sartre

A few considerations:

1)By the standards of previous episodes in the USA Mueller is proceeding quite rapidly. Such investigations start with small fry who can be flipped to testify against bigger fish. A lot there has already happened.

2)Secrecy is a major asset in such investigations. Mueller only releases information via indictments and sentencing memoranda. He is not at a point where he can clearly force Trump to testify or where he can indict Trump.

3)Mueller is being strategic. What would be the point of presenting all of his information at a time when all three branches of government are controlled by Republicans. Mueller is now poised to file against members of Trump's family.

4)The issue of the Trump Campaign conspiring with Russia to influence the outcome of the 2016 election is heavily freighted with political overtones. This issue must wait until Democrats take control of the House - now just a week away.

"It is not necessary to have hope in order to persevere."