I used to think the same thing, because well, I was taught that, but I looked into it a few years back and If I remember the holy Spirit came on people about 90 times recorded in the OT, here are a few examples:
Numbers 11:17 “Then I will come down and speak with you there, and I will take of the Spirit who is upon you, and will put Him upon them; and they shall bear the burden of the people with you, so that you will not bear it all alone.
1 Samuel 16:14 Now the Spirit of the Lord departed from Saul, and an evil spirit from the Lord terrorized him.
1 Samuel 16:13 Then Samuel took the horn of oil and anointed him in the midst of his brothers; and the Spirit of the Lord came mightily upon David from that day forward. And Samuel arose and went to Ramah.
Numbers 11:25 Then the Lord came down in the cloud and spoke to him; and He took of the Spirit who was upon him and placed Him upon the seventy elders. And when the Spirit rested upon them, they prophesied. But they did not do it again.
Isaiah 63:10, "But they rebelled And grieved His Holy Spirit; Therefore He turned Himself to become their enemy, He fought against them."
Numbers 11:17 “Then I will come down and speak with you there, and I will take of the Spirit who is upon you, and will put Him upon them; and they shall bear the burden of the people with you, so that you will not bear it all alone.
1 Samuel 16:14 Now the Spirit of the Lord departed from Saul, and an evil spirit from the Lord terrorized him.
1 Samuel 16:13 Then Samuel took the horn of oil and anointed him in the midst of his brothers; and the Spirit of the Lord came mightily upon David from that day forward. And Samuel arose and went to Ramah.
Numbers 11:25 Then the Lord came down in the cloud and spoke to him; and He took of the Spirit who was upon him and placed Him upon the seventy elders. And when the Spirit rested upon them, they prophesied. But they did not do it again.
Isaiah 63:10, "But they rebelled And grieved His Holy Spirit; Therefore He turned Himself to become their enemy, He fought against them."
Isaiah 11
2And the spirit of the YAHWEH shall rest upon him, the spirit of wisdom and understanding, the spirit of counsel and might, the spirit of knowledge and of the fear of the YAHWEH;