22 For as in Adam all die, even so
in Christ shall all be made alive.
23 But every man in his own order: Christ the firstfruits;
afterward they that are Christ's at his coming.
24
Then cometh the end,
when he shall have delivered up the kingdom to God, even the Father; when he shall have put down all rule and all authority and power.
25 For he must reign, till he hath put all enemies under his feet.
26
The last enemy that shall be destroyed is death.
27 For he hath put all things under his feet. But when he saith all things are put under him, it is manifest that he is excepted, which did put all things under him.
28 And
when all things shall be subdued unto him, [B]then shall the Son also himself be subject unto him that put all things under him,
that God may be all in all.[/B]
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Death is the last enemy that shall be destroyed (Verse 26). Once death is destroyed then Christ will cease to reign (Verse 25). This will all happen at the end (24). The end won't happen till after the second coming of Christ (23). The dead will be made alive at the second coming of Christ (22+23).
Therefore, if the dead have not yet been made alive then
1 Corinthians 15 speaks of events which are yet to happen and thus Christ still reigns and death is not yet destroyed.
Further, all the verses except 27 speak of these things in future tense, mostly evidenced by the use of "shall". (I have bolded the relevant parts).
Further, read
1 Corinthians 15:51-54 for more insight. These verses clearly show that death is not swallowed up in victory until the dead are raised incorruptible...