And, of course, the final road-going production model that follows - if production is confirmed at all - will usually do away with the concept's most awe-inspiring aspects.
The slender futuristic headlights, the low-slung body, the 40-inch wheels that barely fit beneath the impossibly wide guards...
The Suzuki Kizashi 3 concept is another well-remembered example. How different the brand's fortunes in the mid-sized sedan segment might've been if that showstopper had made it to showrooms...
But, every now and then, a car maker hits it out of the park. The new 2017 Lexus LC500, for example.
Of course, there were question marks over whether any future production version could keep the concept's mighty proportions and fine details intact. But Lexus had been starting to demonstrate a move towards a new 'out there' styling language and, it seemed, the odds weren't so bad.
And, as the recent Detroit motor show revealed, those brave enough to bet on the concept's styling will have been stoked to learn that not only is the LF-LC bound for production - but that the resulting LC500 coupe's styling is remarkably true to its roots.
Just how similar are these two cars, though? How faithful is the LC500's design to the LF-LC that came before it?
We've put together a series of comparison shots here. Tell us what you think of the results, in the comments below.
Dead-on, it's clear that the LF-LC is the less 'realistic' of the two vehicles, and that's as it should be - although the photography suggests Lexus used a few lens tricks with the LF-LC shot.
There's no denying, though, that the LC500 has looked to its concept progenitor in arriving at a wide and planted look.
Remarkably, there's very little to set these two twins apart from the profile. Although not outright identical, both feature a super-sleek shape and traditional supercar proportions.
In production form, the LC wears an ever-so-slightly longer roofline, sheetmetal-mounted side mirrors and a proper door handle. There's also a clear and unavoidable panel join at the base of the A-pillar, and the bonnet may be the tiniest bit taller - although that could be the angle of the vehicle in the photo.
Moving to the rear, the photography again suggests a wider look for the LF-LC, but the LC500's muscly haunches are hardly far removed from the concept's intent.
The LF-LC's deep side channels below the tail-lamps are gone, as is the glowing perforated look to the plunging satin-silver trim
A taller rear deck features above a repositioned panel line, and larger exhaust finishers are fitted either side of the subtle diffuser.
It's here that the LC500 delivers the most surprises, with Lexus's designers staying very close to the original headlight and tail-lamp design. In both cases, the design remains remarkably faithful to the concept.
The differences are clear, but the similarities are exceptional. A rare result.
As with the lighting, the big new LC500 coupe's C-pillar has carried over with only minor changes that could arguably be described as an improvement.
The wraparound look continues, while the chrome garnish has been made thicker and the long black side panel now subtly overlapping the glass of the rear window.
Inside is where the bulk of the changes have occurred, and it's no surprise. Lexus has looked back to a more classic design in the cabin, while evolving the long two-tier dash design that has featured in its models for sometime now.
The effect remains rich and premium, however, comfortably matching - if not bettering - the cabins of its European rivals.
And there it is, the LC500 versus LF-LC Styling Faceoff. Has Lexus nailed this one? We reckon it has. Tell us your thoughts in the comments below.