Many did
Start with the people who believed. Fifty days after the resurrection, Peter preached in Jerusalem, the very city where Jesus had been crucified:
"They therefore that received his word were baptized: and there were added in that day about three thousand souls."
Acts 2:41
And then: "the number of the disciples was multiplied very much in Jerusalem: a great multitude also of the priests obeyed the faith" (Acts 6:7).
The risen Jesus "was seen by more than five hundred brethren at once" (1 Corinthians 15:6). Paul wrote that while most of them were still alive to ask.
Isaiah said they would refuse
Isaiah 53, the great prophecy of the crucifixion, opens with a question:
"Who hath believed our report? and to whom is the arm of the Lord revealed?"
Isaias (Isaiah) 53:1
The rejection was part of the prophecy. John saw it happen and pointed straight back to Isaiah:
"And whereas he had done so many miracles before them, they believed not in him: That the saying of Isaias, the prophet, might be fulfilled."
John 12:37 to 38
They saw the miracles
The people who rejected Jesus weren't missing the evidence. They had it. After Jesus raised Lazarus from the dead, the chief priests called a council:
"What do we, for this man doth many miracles? If we let him alone so, all men will believe in him: And the Romans will come, and take away our place and nation."
John 11:47 to 48
They didn't deny the miracles. They were afraid of what the miracles would cost them. "From that day, therefore, they devised to put him to death" (John 11:53). They even planned to kill Lazarus, "because many of the Jews, by reason of him, went away, and believed in Jesus" (John 12:10 to 11).
They paid to cover it up
When the guards at the tomb reported what had happened, the chief priests didn't go and look. They reached for money:
"They gave a great sum of money to the soldiers; Saying: Say you, that his disciples came by night, and stole him away when we were asleep."
Matthew 28:12 to 13
Jesus said why
He told a story about a rich man in torment who begged for someone to be sent back from the dead to warn his brothers. The answer:
"If they hear not Moses and the prophets, neither will they believe if one rise again from the dead."
Luke 16:31
And he put it more plainly still: "the light is come into the world, and men loved darkness rather than the light; for their works were evil" (John 3:19).
The straight answer
Belief was never just about evidence. The evidence was there, in front of them. Thousands looked at it and believed. Others looked at the same miracles, the same empty tomb, and decided they would rather keep their power.
That hasn't changed. The evidence is still here. Every page of this site is part of it.