The romanian AK bayonet is made from a carbon steel much cheaper than INFI and it's a few decades old model still in production. You can see the tests performed by Noss on it at knifetests.com and (what I actually want to say) it has extremely high lateral strength. I don't know if it's equal to INFI or lower or higher (have no idea because I didn't see knives with similar sizes and shape tested the same way; however, lots of thicker modern knives failed the body weight test). But in Noss tests you can see this bayonet taking all his weight balancing and passing the body weight test without problems. That's a 3 millimeters thick bayonet and 3 centimeters wide. It broke at the flex test because of that hole into the blade which weakens it. I also have a romanian bayonet older model which was used in World War II and that's also extremely strong for lateral strength. Of course, excepting lateral strength and (maybe) impact resistance, these bayonets are not excelling in other areas. Especially the AK one is very poor at edge retention and rust resistance. But what I want to say is that strong steel existed in the past and few hundred years ago too.

Newdays, knife makers are focusing on optimizing production costs and on obtaining superior edge retention and stainlessness. But for toughness and hard use resistance, after my knowledge, we are unfortunately behind old times as average. There are very few knives today which can really compete with high grade fighting tools that existed long time ago. But the costs are significantly lower today, so that anybody can achieve a good knife, comparing with old times when a good Japanese katana was requiring sometimes 2 or 3 generations of sword makers to finish it. So, of course, I'm very happy I can afford INFI today for just a part of my monthly income and not wait tens of years and pay with a life of work to get one. But that doesn't mean the knives we have today are the best in history.

So my opinion and knowledge is that we are today in the top of the history with stainlessness and edge retention on available knives that are produced today, but not in the top regarding toughness and strength. The really tough knives today are rear and very few. I also think today we have the best quality-price ratio in the history and affordability... and maybe we also have the best all-around knives.