The Scriptures tell us:
The times of ignorance God overlooked, but now he commands all people everywhere to repent, because he has fixed a day on which he will judge the world in righteousness by a man whom he has appointed; and of this he has given assurance to all by raising him from the dead. – Acts 17:30–31 ESV (emphasis mine)
...the gate is narrow and the way is hard that leads to life, and those who find it are few. – Matthew 7:14 ESV
The unavoidable conclusion is that most people that hear the call to repentance, either ignore, resist or reject it (this sadly, also accords with our experience).
A common Reformed argument* (e.g.) against the doctrine of General Atonement, is that a non-efficacious (in terms of its intended scope) Atonement is not consistent with the Sovereignty of God – on the surface, a reasonable argument, particularly from a Reformed perspective of the Sovereignty of God that rests on Unconditional Election and Irresistable Grace. From a Reformed perspective, how is a non-efficacious (again, in terms of its intended scope) call to repentance any different in this respect? Why isn't that equally inconsistent with the Sovereignty of God?
If a King bids a man to come, and the man comes not, is this not an affront to the King's sovereignty?
*Edit: Ok, so maybe it's not as common as I thought, and possibly not strictly logical, but here is some evidence that it is advanced by people who should be able to articulate a consistent position:
"Unlimited atonement is inconsistent with the sovereignty of God." - Rev. Steven Houck, Immanuel Protestant Reformed Church Lacombe, Alberta. source
"Proponents of limited atonement often make a fifth argument, which is that unlimited atonement cannot be reconciled with God's sovereignty." - p200 Salvation and Sovereignty: A Molinist Approach By Kenneth Keathley. source