Explanation for the delay is given in this article.
Seems they have some significant people wired and are gathering good information
Thanks. The 50,000 number being bandied about is to cover this up, from your link:
The FBI failed to preserve five months worth of text messages exchanged between Peter Strzok and Lisa Page, the two FBI employees who made pro-Clinton and anti-Trump comments while working on the Clinton email and the Russia collusion investigations.
The disclosure was made Friday in a letter sent by the Justice Department to the Senate Homeland Security and Governmental Affairs Committee (HSGAC).
The Department wants to bring to your attention that the FBIs technical system for retaining text messages sent and received on FBI mobile devices failed to preserve text messages for Mr. Strzok and Ms. Page, Stephen Boyd, the assistant attorney general for legislative affairs at the Justice Department, wrote to Wisconsin Sen. Ron Johnson, the chairman of HSGAC.
He said that texts are missing for the period between Dec. 14, 2016 and May 17, 2017.