Absolutely, historical swords are collectible and appreciate in value, whether Japanese or European, basically up until WW2.
Knives that are historical also tend to go up in value. Unfortunately, by the time a knife is historical, it's too late to get them because, well, now they're historical.
Some knifemakers have persistently increased in value - think Bo Randall originals, Bob Loveless, Rudy Ruana, etc. But relatively few do.
Ironically, my theory is that some living, popular makers with presences on social media are in a lot of ways better 'investments' because they have a popular following and their knives are immediately worth way over table price. But older makers, even historically significant ones, gradually fade from the collective memory as no new knives or Blade Show prizes or viral InstaTwitFace posts are produced, until only diehard historical collectors (who are a minority compared to the InstaWhatsIt crowds) remain.
And the kicker of course is that you really never know who's going to be popular long-term. There's no way to predict early enough to get in on the ground floor of a maker who ends up being really popular, especially not historically popular. The odds of getting in early with the next Loveless are low. The only ones that reliably accrue value are ones that have already proven to accrue value. There will always be historical sword and knife collectors.
Example: I had a book order with Peter Carey back in the early 2000s when a full-dress Nitro would be $650. I had to pass when my spot came up. Now they're like $2,250, and his books are long closed. Who could have known? On the other hand... I won a great dagger from Matt Martin of Vehement Knives in a raffle. Spent like $200 on raffle tickets. Later on, sold the knife instantly in his Facebook group for $3,200.
Long and short of it: There's only one way to make a small fortune investing in knives. First, start with a large fortune, then start buying knives.