The "drama" is that out of the four key candidates you mentioned (Biryukov, Sivo, Ilinykh, Spir) only Biryukov played whole season as a starter, on a good level. Ilinykh has been very seriously on the bench and so was Spir. Sivo played but not as much as one would want to; he and Spir had various injuries last year. After that, Biryukov does seem not to get along well with Voronkov: as we may remember he sat all the WCh on the bench in favour of Savin/Spir, for which Voronkov was criticised publicly by Alekno, a very rare situation in Russian volleyball.
The drama I was actually referring to was the lack-of-choice one, the one usually mentioned every now and then The drama about how Russia suddenly struggles to find decent OHs. And I might be paraphrasing here from other posts and threads. It is indeed a totally different question in what shape the aformentioned players are. I know very well how much each one of those has played this year, but as we see there are quite a lot of alternatives and talented youngsters waiting for a chance Besides, those on the bench should be fresh for the summer season, right?