The tree appears to have several issues...including a possible lightning strike years ago, some dieback and decay, and intertwining branches, all of which contribute to its declining nature. Growing on a lawn and near a road/path also aren't helpful due to soil compaction and getting hit by lawnmowers. Regardless of those things, trees can surprise you at times and this one could take several years (decades) to die.

If it were a highly prized tree for some reason or as Ken said, growing on someone else's property, I'd leave it alone.

If it's your own tree and you don't really care one way or the other, I'd tap it, but only one tap and take care in the placement to be sure you hit good wood. Typically you "adjust" the diameter of trees based upon stem/crown wounds, so although it may be 24+" dbh, the "adjusted" size is considerably smaller than that.

The alternative philosophy if you have observed it fading fast would be to heavily tap it given that it'll be firewood within a short time anyhow.