Or, Yeshua/Joshua, as his real name is.
Greg Koukl seeks to answer this question, but fails at square 1. But, he's a Calvinist, so can't help himself, unhappily so.
Yeshua is the only 'way' because he is the creator!
The only alternative way would be within the creation, indeed, the creation itself. And the problem is the whole creation is alienated from the creator because man has turned against his creator from the get go.
As the creature in God's image, created to enjoy free fellowship with God, created to steward the great playground of the material creation, when man falls, it all comes down around his ears. So looking for the way in the creation is like doing a burnout in a cul-de-sac. You get nowhere, make lots of noise and smoke in empty show, and destroy stuff.
Yeshua offers new life if we turn and reject the life of rejection of creator (him) and alienation within the creation.
The signal of the alienation and futility of the world adrift is that we are not linked to God: this is in our souls. We know we are not what we should be. We are not with the one who made us because the link is broken. The ancient Jews were told this in the Torah, in distinction to the paganism (the 'worldism') surrounding them: the 'law' that tells us what God is like. But he provided forgiveness then under Torah, and now in Yeshua. Personally.