The preview screener for “Downton Abbey” is due shortly, and from a critical perspective, the follow-up to PBS’ Emmy-winning miniseries can’t arrive a moment too soon.

Because despite a recent mini-resurgence in longform projects — on an alphabet soup of cable venues not regularly associated with them, including TNT, Syfy, A&E, MTV, USA and CMT — there has been one rather disheartening common thread.

Where is it written, exactly, that these movies and miniseries must be so consistently lousy?

However uncharitable that sounds, watching a multitude of these productions (and that’s a job requirement, not a recommendation) reflects a “comeback” in volume only. Most of the movies not only have a decidedly dated feel but appear to have been stripped of all flavor — if not outright lobotomized — for easy consumption.

Even the normally reliable “Hallmark Hall of Fame” — one of TV’s most storied franchises despite an uneven track record in recent years — just inaugurated its new ABC deal with one of its worst efforts in memory, the self-aggrandizing, painfully sappy “Mitch Albom’s Have a Little Faith.”

For those seeking signs of a higher power, “Faith’s” mediocre ratings at least say something moderately reassuring about the card-buying audience.

Admittedly, those who have remained active in TV movies throughout its downturn — outlets like the Hallmark Channel and Lifetime — seldom challenge their viewers, content to return to a formula meant to be as snuggly as a winter blanket.

In terms of quality, it’s been left to HBO — which has the luxury of strategically offering a handful of high-profile titles for maximum publicity and awards impact, not ratings — and PBS’ “Masterpiece” to vie for attention, with the pubcaster’s classy British dramas having been especially strong the last few seasons.

On the one hand, strictly from a humanitarian/employment standpoint, it’s tempting to not look a gift horse in the mouth. After all, there’s been understandable lamentation in many quarters — including this one — about jobs lost as the made-for-TV movie business dwindled from 200 to 250 titles a year during old three-network “Sunday night movie” days to perhaps several dozen. It’s nice to see actors, writers and crews working, even if it’s on schlock.

Nevertheless, it’s difficult to understand why reviving a genre associated with the 1980s and ’90s means looking so retro. And in terms of attracting younger viewers — a high hurdle even under ideal circumstances — trotting out a parade of such stale concepts is likely to become a self-fulfilling prophecy. About all that’s missing from the current wave is a trashy update featuring infamous TV-movie fave Amy Fisher, the one-time “Long Island Lolita” who — now a cougar-ish 37 — recently participated in a celebrity boxing match and could probably use the money.

Indeed, beyond this month’s numbing onslaught of Christmas-themed movies (among them Syfy’s “Snowmageddon,” about a killer snow globe), the marquee titles are all retreads, aping stuff that drew big ratings on the major networks ages ago. Examples range from the Albom pic (think “Tuesdays With Morrie”) to A&E’s Stephen King miniseries “Bag of Bones” and Syfy’s Peter Pan-inspired “Neverland,” RHI Entertainment’s latest bastardization of a beloved classic.

Then again, those productions underscore how dramatically the telefilm landscape has shifted. And while the audiences they deliver will surely be puny compared to the mass appeal of Robert Halmi Sr.’s fantasy epics and King adaptations in their broadcasting heyday, the numbers ought to be good enough judged by their new cable homes’ lower standards to allow them to declare victory.

The producers who have survived in this sphere certainly deserve some sympathy, and whatever their ambitions, they’re ultimately only as good as what the networks — seemingly content to rehash the not-so-good old days — are willing to buy.

There are ways to help limited production dollars go farther, from the crapshoot of allowing stars to dabble in passion projects to movies that double as backdoor pilots.

Either way, if the TV movie’s return is going to amount to more than a flash in the pan, this is no time to party like it’s 1995. And speaking of parties, a raucous bash contained in another movie comes to mind — only in this case, let’s not do the time warp again.