You appear to be under the impression that "I (you, he, etc) will X" is
"the future tense" of the English verb X.
No. I specifically mentioned that both English and Hebrew use grammatical
future tense in idiomatic form. That form originally arosed from the future
tense, but later idiomatic forms became semantically different from future
time reference. Neither in English, nor in Hebrew that development
invalidates existence of tenses in general.