Here's what I mean:
1. Go to this link: http://erg.delph-in.net/logon .
2. Type in "I will go to the store" and check "mrs" in the output list.
3. Click "Analyze"
4. In the MRS (right pane), under "go_v_1", hover over the "e3" of the "ARG0 e3" line.
5. You'll see "TENSE fut" in the feature box.
That's the result of a symbolic, machine grammar, not a machine-learning system. A rules-based system was able to determine that the verb is future tense (based on a syntactic rule that unifies in the future tense based on the presence of the auxiliary).
If aliens came by and zapped every English speaker's brain so that we all started using "I gowill to the store and buywill some fruits" instead of an auxiliary, that would be a simple adjustment to that grammar (delete the old syntax rule, add a will-lex rule to strip the suffix and apply the same feature to the verb).
If, then, another set of aliens came and zapped our brains again, deleting all memory of the concept of "will X" from our heads, that would be different. In the presence of the sentence "I go to the store tomorrow" or "I write code next year", there's no way for any symbolic grammar to handle all the possible ways you can contextually refer to the future. That's solely the domain of ML systems (and all their faults), at least as far as I know.
-------
By analogy, the way people talk about English future tense is like if people said "Python doesn't have closures with more than one statement", and when questioned "Well inline function definitions in Python have closure", they responded "Well of course I meant 'Python doesn't have expression closures with more than one statement'". Like sure, it's true and even a valid clipping to make in a certain context, but as it spreads as a meme people who don't know the context get the wrong idea.