Like the title says: I don't think "to can" is right :) I mean "can" as in to be able to. I'm aware of other meanings. I can't find the answer here. (There's What is an "infinitive"? which ...
Why are some verbs only usable in the infinitive? The one example I can think of is "to spite" (see "to wit in the accepted answer). While wiktionary claims that spited is a word, that doesn't match ...