There's an interesting symmetry to Richard Plepler's run at HBO, during which an upstart premium cable channel would eventually redefine television and then for a long while wear the mantle as the ultimate home of boutique, high-end programming.

That all ended Thursday when Plepler stepped down amid a reorganization for the streaming future that will, in many ways, make HBO less of what it's always been and more of something else, yet to be defined.

That makes Plepler's rise through the ranks and sustained tenure emblematic of what was but isn't so much anymore. It was mostly glory and glitter in HBO's early days, but eventually channels like Showtime and then especially FX and AMC fought to be mentioned successfully in the same breath as equals. And yet, HBO was always HBO and everybody else just wasn't, so even in the channel's leaner years, the patina didn’t get too tarnished.

But then the advent of streaming came and Netflix was first and fastest out of the gate and has been HBO's biggest nemesis ever since — but it was always a rivalry that both sides played down for different reasons. HBO scoffed at Netflix's catch-all programming, which often lacked HBO's prestige. And Netflix, in turn, never considered HBO a real rival because it was so much bigger — an international company — and, it believed, correctly, that the future was always going to be non-linear.

After AT&T bought HBO's parent company, Time Warner, there were a lot of disparate parts operating too separately for the liking of a telecom giant that was less interested in, say, HBO being one thing and TNT, TBS and truTV under the Turner name-plate being something else, because that's just not how non-media companies operate. So change was always coming in some form and the biggest manifestation of that was the creation of WarnerMedia, the umbrella for all the merged brands.

WarnerMedia is, of course, finally getting into the streaming wars this year and more concretely in 2020, joining Apple and Disney+ as the newest big dogs.

Last summer, former AT&T and now WarnerMedia CEO John Stankey gave HBO the very non-boutique news that it needed to be bigger, work harder, be broader and make more money. It was a wake-up call that essentially signaled the end of what HBO once was and what it, under the direction of a company with big ideas and big dollars, could hope to be.

You would have to think that at some point in that hot-topic meeting or sometime shortly thereafter, Plepler knew the run was going to come to an end.

Plepler started in corporate communications in 1992, then worked for Jeff Bewkes, the former CEO of Time Warner but then head of HBO, a move that brought him a glimpse of power and control; he rose to a co-president role along with Michael Lombardo in 2007, just after Chris Albrecht, the architect of HBO's storied push into original programming, was arrested for assaulting his girlfriend in Las Vegas; then, splitting off from Lombardo, he became CEO and chairman in 2013.

Always in on the deal and the direction of the company and its brand, but seen less as the main creative person (that fell to Lombardo, who was eventually replaced as president of programming in 2016 by Casey Bloys), Plepler was the bigger behind-the-scenes executive. But with a bigger company controlling things and a much bigger idea for the future — streaming — WarnerMedia first turned to Turner entertainment head Kevin Reilly, who had revamped TNT and TBS, to be chief creative content officer for WarnerMedia's streaming efforts. And this week, The Hollywood Reporter reported that WarnerMedia, in its continuing shake-up and makeover, might be bringing in former NBC and Showtime head Bob Greenblatt in a major role.

Two days later, Plepler stepped down.

It was certainly an amazing run for Plepler over the years, from corporate communications to CEO and chairman. It could be argued that the critical years were 2007 to 2012, when he and Lombardo abruptly took over for Albrecht and were viewed, at the time, as neophytes and more buttoned-up than the free-wheeling Albrecht, who had guided HBO to lofty heights. The immediate task for Plepler and Lombardo at the time was simple: Don't blow it. Unwritten was something almost as important: Make great, gold-standard shows first, worry about popularity later.

In that period came Game of Thrones, Girls and Veep, which were the signature shows; plus Treme, Boardwalk Empire, True Blood, In Treatment and The Newsroom — a mix of high-quality and big swings; plus less successful or notable fare like Luck, Bored to Death, Eastbound & Down, Enlightened, Hung, How to Make It in America, Life's Too Short, The No. 1 Ladies Detective Agency, etc.

A CEO and chairman often gets less blame (and less credit) for series that the programming chief is the public face of, so it's difficult and maybe dubious to link Plepler with Bloys, though he undoubtedly had plenty of say. What's clear, however, is that Stankey wanted WarnerMedia to scale up for a battle not only with Netflix, Amazon and Hulu, but with Disney+ and Apple as well, and he viewed HBO in the same prism that everybody else did, especially as it sat next to Netflix — a boutique.

The question in the industry is whether HBO with more shows (and ostensibly more money to make them) will still be HBO as everyone knows it — hands on, supportive of creative swings, even if they don't connect. Or will it lose that personal touch? Maybe Plepler, with 27 years of service, already knew that answer and didn't want to be around when the legacy shifted. Or maybe, in the era of the conglomerate where AT&T was going to be more hands on than off, someone from above telegraphed that new direction.