In my opinion yes but the same thing can be said about a lower quality dot com.
Let’s assume you want to launch a website about furniture. Furniture.com would obviously be the best possible domain but most companies (the overwhelming majority) definitely can’t afford it.
Therefore, they have to make a decision.
In most cases, the decision is simple and there are two broad categories of choices:
1) A longer dot com such as GreatFurniture.com
2) The same keyword but in another gTLD, so for example Furniture.gtld
Is traffic leakage a threat?
Well yes, in both cases.
If you own Furniture.gtld then sure, there will be some leakage to the dot com but don’t make the mistake of assuming that such a threat doesn’t exist for domains such as GreatFurniture.com.
GreatFurniture.com, GoodFurniture.com, BestFurniture.com, these are all commonly used adjectives and as such, people will in some cases make confusions. If you add one more word, so if you have to settle for let’s say YourGreatFurniture.com instead of GreatFurniture.com, the traffic leakage/confusion issue becomes even bigger.
Is It YourGoodFurniture.com? Or MyGreatFurniture.com? Or OurBestFurniture.com? I’m sure you get the point.
The conclusion is simple: the greater the “distance” is between your domain and the category killer of that industry (Furniture.com in our case), the more traffic leakage potential there is.
Therefore, it’s all a fine balancing act at the end of the day.
Businesses will have to decide, based on budget-related arguments among other things, how much they are willing to pay for a domain.
In some cases, a longer dot com would represent the best choice.
In other cases, a new gTLD alternative would represent the best choice.
It all depends, there’s no “one size fits all” answer unfortunately. On a case by case basis, it’s the responsibility of each company to make the right choice. I simply wanted to point out that traffic leakage isn’t only an issue for non-dot-coms, dot com domains can be and are also affected.