Exactly a year ago, your humble correspondent suggested in this very space that ABC and NBC — more by happenstance than choice — were joined at the hip.

“Television is no longer a zero-sum game, in strict ‘for me to win at 8 p.m., you have to lose’ terms,” that column stated. “But it is a landscape of finite resources — including advertiser loot, cultural buzz and claims upon the audience prone to commit to series — and with CBS and Fox each staking out their own distinctive turf, ABC and NBC appear stuck in the middle with each other.”

Those words turned out to be prescient, if the two lineups the networks just presented to advertisers are any indication.

Admittedly, ABC has more arrows in its quiver right now than NBC does. Yet the parallels between the programs the two ultimately scheduled speaks volumes about the overlapping profiles they are cultivating, the bets they’re making and the marginal distance separating them. These choices, moreover, are in fairly stark contrast with CBS and Fox, two networks occupying more clearly defined real estate.

In the most striking mirrored efforts, both ABC and NBC ordered glamorous serials set in the early 1960s — “Pan Am” and “The Playboy Club,” respectively — and each scheduled a macabre drama rooted in the underlying truth behind classic fairy tales, NBC’s “Grimm” and ABC’s “Once Upon a Time.”

Yet those instances of convergent evolution — that is, two networks simultaneously birthing almost the same show, which inevitably happens now and then — are only the most ostentatious of many similarities.

Both networks feature new management that began after the 2010 campaign began. Each entertainment division is steered by an executive who won rave reviews for developing attention-getting cable shows. NBC’s Robert Greenblatt and ABC’s Paul Lee have each had just enough time to place their stamp on the upcoming season, but they can still lay most deficiencies at the feet of predecessors, and owe them credit for what’s currently working.

Both are relying on super-sized reality shows and Friday-night newsmagazines to plug gaps. Both are braving the launch of an 8 p.m. comedy hour. And now NBC too has a competition program, “The Voice,” to potentially narrow ABC’s most conspicuous advantage thanks to “Dancing With the Stars.”

Neither can point to much cohesion regarding their new programming, which reflects a certain let’s-throw-a-lot-of-stuff-against-the-wall experimentation. Soaps, sci-fi, a period piece, crime procedurals. Hey, maybe we’ll get lucky with something.

On the flip side, while some of their series look more promis-ing than others, the bets placed by CBS and Fox don’t represent serious departures from what they’ve done in the past.

Fox’s biggest financial gamble — the family sci-fi concept “Terra Nova” — goes directly into the hour where the network tried another show cut from the same cloth three years ago, “Terminator: The Sarah Connor Chronicles.”

CBS shifts an aging “CSI” to a different night, but replaces it with “Person of Interest,” another concept with solid procedural underpinnings.

Small wonder that CBS execs used their upfront presentation to not-so-subtly hammer away at how selective and targeted they could afford to be in their development. Unlike the other guys (ABC ordered 13 new series for next season, NBC 12), they don’t have a multitude of frosh programs to sell — “a high-class problem,” as CBS Entertainment prez Nina Tassler put it, following CEO Leslie Moonves’ line, “We don’t rebuild. We reload.”

Fox, too, could tout its uncharacteristic stability, especially with another competition show, Simon Cowell’s “The X Factor,” filling the same hours during the fall that “Idol” will occupy come January. Even in a DVR age, knowing where shows are matters.

While ABC’s Lee was relentlessly upbeat in his pitch to advertisers, Greenblatt sounded more restrained. Yes, rebuilding will require time, but he reassured the room that NBC parent Comcast has the corporate will and resources to get the job done.

Hard sell or soft, last May’s appraisal appears even more accurate today: CBS and Fox are running in “clearly marked lanes” — the total-viewer leader and demo champ — while ABC and NBC jockey in the middle.

As for how that race plays out, unlike the fairy tales finding a home on each network, in primetime there are only so many “happily ever afters” to go around.