6 cars that have been overshadowed by their "siblings"
When creating a new car, there are several layers and several steps. First you have to design it and engineer it and that is costly. In fact, it is easily the most expensive part because the actual, physical production isn't that expensive in relative terms. And even if marketing, promotion and communications are becoming increasingly crucial steps of the sale process, and therefore progressively more expensive, the cost to sustain is, again, relatively low.
Somewhere along the line car companies realized that they could offset the cost of designing and engineering new cars by using old and/or sharing new ones. This has always been done, it's just it's becoming exponentially more common.
A lot of cars made by VW, for instance, are based on either the Golf or the Polo. In the same way that the C/D-Class platform by Ford, another example, is used as the basic structure to build the Fusion, the Mondeo, the Edge, the S-Max, two more Ford models and three Lincoln cars.
Sharing platforms is the main thing but it's not the only thing. The list that follows also includes other cars that undersold or were ignored because there was another, more practical or more sensible, similar car in the family.
The VW Phaeton was designed on the same platform that was used for the Bentley Continental GT and the Flying Spur and with the North-American market in mind. It shared some components with the Audi A8 and it was available with five petrol engines, including the monstrous 6-litre W12 with 444 HP and four diesels, including the amusing 5-litre V10 with 750 NM of torque. It was a good car, I remember driving it once and it felt majestic. However, there were two major issues: its price and its badge. People weren't ready for an upmarket Volkswagen, it was in the same segment as the Mercedes S-Class and the 7 Series BMW and, more importantly, as the Audi A8. However, precisely because these two cars were so closely related similar in price, even when buyers shunned the Beamer or the Benz, they would go for the Audi because it had a better badge.
Volkswagen Golf Mk5 R32 (2005-2008)
The obvious issue with the Golf R32 was its sister, the Golf GTI. The R32 had a wondrous engine. It was a naturally-aspirated 3,2-litre V6 with 247 HP but unfortunately this amazing engine was also its main problem because it was more expensive to buy and much more expensive to run than the GTI while being only marginally faster. The top speed was 155 mph but the GTI could do 145 mph and from zero to sixty the R32 was only 0,7 seconds quicker than its sibling. Better, yes, but not enough to justify the difference in price.
Renault Avantime (2001-2003)
A lot of people will probably say that the Avantime flopped because it was a bad car, but it wasn't. It was similar to the Espace in size, but more interesting and that, along with the fact that it was only available as a three-door, was its problem: it was different. Just look at the list of best-selling cars, it is full of predictable, conservative cars. It was an outside-the-box kind of car and unfortunately, whether we like to admit this or not, outside the box usually doesn't sell. This meant that the average Renault MPV buyer would look at the Avantime and say "wow, that's really cool. Ok, now back to the Espace I was inquiring about". Pity.
Lancia Delta (2008-2014)
It is safe to say that the name was its first problem. Using an iconic name to market and sell a brand new car that has very little in common with the original car that made the name in question is always a risky business. It is even worse when the car in question flops commercially. The 2008 Lancia Delta wasn't even a bad car because it had decent looks, acceptable interior quality and a super-quick twin-turbo diesel with a lot of torque. But it was too expensive for what it was and it ended up being hurt by competition, especially in the family. Because why buy the Delta when you can have the cheaper Bravo, which was basically the same car underneath, or even the Punto? It wasn't good enough to justify to extra cost.
Land Rover Discovery (2017-present)
Quite apart from the weird-looking tailgate, the new Discovery (5th Gen) has three issues: they're called Evoque, F-Pace and Range Rover. The F-Pace and the Discovery are in a similar price bracket and because Jaguar and Land Rover are now more than ever two members of the same two-man band (JLR), it's likely that a potential Discovery buyer will go to the dealership and see the Jaguar F-Pace, and that is a much better looking option at a similar price. Other buyers might be tempted but will end up saving a little money and getting the smaller, cheaper Evoque instead and, on the other end of the scale, other buyers might be persuaded to spend a little more and get the "daddy", the Range Rover, or even the Range Rover Sport. You can add the Velar to the equation if you like, because it looks better than any of the cars I've mentioned so far. The Discovery has an odd tailgate, yes, but its real shortcoming is that it doesn't have a market bracket it can fit into, and isn't strong enough to create one of its own.
Ford Flex (2009-present)
Personally, I like the Ford Flex a lot because I think it looks great. However, the Flex is only marketed in some parts of the Middle East and in North America and there are other Fords that are sold in the same regions with similar characteristics. Like the Ford Edge, for example, or the Expedition or, and this is the real deal here, the Explorer, which regularly outsells the Flex by astounding margins. Not to mention cars made by Lincoln, part of the Ford family.