Personal opinion below. Started as comment, became too long.
Once upon a time, Jeff used to write blogs about actual things he did, and features of Stack Overflow, e.g. moderation, email notifications, etc. The rest of the team followed his lead and posted useful and interesting things about SE/SO itself, e.g. Reputation and Historical Archives by Josh.
Big changes were announced back then by blog posts, e.g. new top bar back in 2013.
These days, none of this exists. It has been replaced with blogs that just advertise/promote various products of Stack Overflow. There are rare posts about new features, e.g. How Stack Overflow Redesigned the Top Navigation but most features go without any blog post announcement, e.g. the network wide new top bar which is nothing like the Stack Overflow top bar. That's a great miss. Even if they'll post blog posts about new features, they will be drowned and buried beneath the others, with charts and calculators, which are nice for some and useful for others (and I do respect those who spent time and efforts to write them!), but as this discussion made me realize, not great anymore. Not in the way it used to be. The focus shifted from the actual developnent of stuff and the Q&A part, to the money-making products of Stack Overflow the company.