Actually, this is something that I have been thinking about for quite awhile - mainly because I have aspirations of wandering into the industry sometime soon and am hopeful there is room for at least one more.
Honestly though, there are three trends right now that are significantly helping the knife industry as a whole, and the high end side in particular ... but there are also some trends making it more difficult.
First, the population of the US is getting older, and the average wage is increasing. Basically, this means that the people who are interested in buying knives are more and more people with more disposable income, and typically people that are not buying their first knife, so they are able to get over some of the first time jitters in doing so. This trend is actually having an impact across alot of industries, and to some extent seems to be holding even despite the current economic slump.
Second, it is getting alot harder to buy a firearm than it used to be. The increase in difficulty associated with these regulations has actually caused a decline in the total number of firearms purchased in the US over the last year or so (assuming you can believe the New York Times) and a reasonable percentage of those people who would spend their money on firearms are shifting to knives.
Third, there are actually a new group of military veterans that have come out of active service, have seen conflicts and are part of the civilian work force. The Desert Storm/Shield, veterans have now been in the work force for a bit, and military personnel coming into the civilian world tend to jump into the knives/guns industries.
However, there has also been an absolutely enormous explosion in the number of knife companies out there over the last 10 years. Even companies which are more veteran, like SOG and Spyderco are only in the 15 to 20 year old range, compared to companies like Buck. With the overall trends of an increase in "tactical" knives, and a popularization of "weapon violence" as an issue, we are all seeing more restrictive knife legislation, and "sheeple" sentiment.
In my humble opinion - the industry will continue to grow. Firearms are much more easily legislated against because they are not so versatile. The fact that a drywaller, hunter, LEO, and hobbiest might all prefer the same knife (a REKAT SIFU - for Glockman
) indicates that legislating based on need or purpose is going to be difficult in the long run. Further, the quality and variety of product is getting better, and the market is becoming more educated. 10 - 15 years ago, $100 for a knife was outrageous to many common knife buyers, but now it is far more accepted. It may be that the average price of knives have stabilized again (I note that SpeedTech went out of business and their products tended to push the higher price line as a data point) but I think the market is more prepared for even more new products and ideas as related innovations come out.
So I think there will be room for growth ... and one more high tech trick lock knife company.
