I realize, Hussein, that my post above was not very momentous. I was aware when I made the post that it probably would not come as a great surprise to you that the sentence with "will usually" could be used to refer to a future habit. But I thought you might be interested to know, and appreciate knowing, that that is the context I find most natural for that sentence as a native speaker.
The fact is, Hussein, I find the sentence "He'll usually go to work by bicycle" to be very awkward if it is to mean that he presently has that habit. Having thought some more about it, I have realized that it is not because of "will" but because of the adverb "usually." If that sentence (with "will") is to refer to a present habit, it would be far better, in my view, to use "often" instead of "usually."
(b1) He will often go to work by bicycle.
(b2) He will often sleep until noon on Saturdays.
(b3) He will often show up late to work.
Instead of "often" I could have used "sometimes" or other adverbs or adverbials. The reason I chose "often" is that it is rather close to "usually." I do, however, think that there is a difference in meaning between the two. Looking at (b3), we see that "often" indicates "frequently" -- and that doesn't imply "usually." It could be that, on most days, he gets to work on time; but he is prone to being late.
Thus, when "will [verb phrase]" is to refer to a present habit, the adverb that one inserts should not, in my view, be the same type of adverb that one would use with regular present habits. "Will often [verb phrase]" can refer to what I shall call predictable aberrations of behavior, as in "He usually gets up at the crack of dawn, but he will often sleep in on Saturdays." There is a certain willfulness about "will" here.
Having said all that, I did think of one syntactic context in which I would not find it very awkward for "He will usually [verb phrase]" to refer to a present habit, and that is a context in which a time-clause adverbial modifies the entire statement. Notice that this changes the meaning of "usually" from "the usual course of things" to "usual under this circumstance." For example:
(c) He will usually go to work by bicycle when his wife needs the family car for the day.
Now you know what I had cooking behind my first post in this thread. Often what I say overtly in a thread is but the tip of the iceberg of what I'd like to say but for whatever reason am not ready to commit to publicly as moderator.