We live in one of the wealthiest countries in the most affluent times in history. Even the poorest American Christians live better off than most of the world. The material things we enjoy are undoubtedly a blessing from God. But just because we enjoy material blessings does not necessarily mean that God is pleased with our spiritual condition.
The church at Laodicea made the mistake of thinking that because they were wealthy, then they had everything they needed. They were materialistic because they made money, or the lack of it, the standard by which they judged the rightness or wrongness of anything. They thought their wealth was proof of their spiritual health. They did not know that they were in a miserable state. They had plenty of money, but they were spiritually destitute. They had the nicest clothes, but they were spiritually exposed. Their physical vision might have been 20/20, but they were spiritually blind.
God’s counsel in Revelation 3:18 is to make God the source of your satisfaction and find everything that you need in Him. You need faith in God, Christ’s righteousness, and the Holy Spirit to correct your spiritual vision. You do not need more money, better clothes, or better health. What you really need is God.