When people say English doesn't have a future tense, they mean it doesn't have an inflectional future tense like other languages. It uses modal auxiliaries inst

When people say English doesn't have a future tense, they mean it doesn't have an inflectional future tense like other languages. It uses modal auxiliaries instead, as in your examples. Compare "I walked" (inflection) with the simple future "I will walk" ("will" as a modal auxiliary).