The actual answer is 'No'! as Ben has said it MAY result in higher margins but penetrating a market depends on many factors not least competition, costs, the ability to create an appropriate offer and the position achieved.
VW moved upmarket with the Phaeton which is priced around £45k. [the top Passat is arounf £26k]. Which I understand doesn't cover the cost , let alone contribute to any return on investment!
They built a dedicated factory in Dresden. The design and quality are reputed to be of very high quality - one criterion was apparently the a coin could be sttod on edge on the bonnet while the engine was running, and stay there with no vibration shaking it off. But their chief executive admitted they would never make a profit on the venture.
A brilliant luxury car - but a Volkswagen - 'People's Car'
Maybe had they invested a little more and made it a bit bigger and branded it 'Bentley' maybe they could have been very profitable.
So it is down to marketing competence and targeting the right market segment with the right offer.

Moving up market can allow a business to increase the sale price of the product therefor increasing profit margin. However it depends on how moving up market effects the cost of the product to produce.
The cost of moving up market may decrease profit margins if the cost of production increases at a higher rate than sale price due to more expensive components.

An example might be

Tesco own brand television
£100 to manufacture. Selling at £200. Making £100 Profit on each unit

Compared to the latest Sony 3D T.V
£920 to manufacture. Selling at £1000. Making only £80 Profit on each unit

This is an example I created and is not fact but I hope it helps.

I agree with Ben's answer, but think the question is a little simplistic. You always have to consider total revenue as well as margin, as profits = margin x sales.
So a company may choose to go low margin if it means there are more sales there so overall profits are higher. For example a Ford focus will be low margin Vs a Ferrari, but you'll sell a million Fords for every Ferrari so probably worth it overall.

In terms of other examples I would look at cars again. Some cars will produced at no margin, or at a loss, but will "Halo" over the rest of the range making them more prestigious. For example a company like Aston Marton might do a special edition vehicle that is at the top of their range and low margin, as they'll get publicity from it which will increase sales at the lower of more affordable and higher margin cars.

Another good example is pet food. Basic pet food is very cheap to produce, so maybe cost of goods are about 5p/can and it's sold at £0.80, so a margin of approx 75p/can or 94% (excluding taxes etc). Premium dog food has much lower economies of scale and higher costs so could be up to 50p/can and is sold only at a slight premium of say £1/can.
As such the margin in both absolute and percent terms is lower.