The entire book seems to be about the contrast between the Law of the Hebrew Scriptures (Old Testament) and the Promise of Jesus. The Writer is constantly pitting the two against each other, much to the dismay of his contemporaries I'm sure. Many today would also have heartburn over this.
But I don't think that the Writer is trying to disrespect the Law or Moses or the history. I think he's saying it's evolved, improved, and culminated in the Person of Jesus Christ. So, in chapter 10, he points out that the sacrifices under the law were required, but were not sufficient. Then he quotes and commentates on Jeremiah like this: " 'Their sins and lawless acts I will remember no more.' And where these have been forgiven, there is no longer any sacrifice for sin." This is a RADICAL change for former Jews who now follow Jesus.
Which makes the famous verses 24-25 more meaningful to me: "Let us consider how we may spur one another on toward love and good deeds. Let us not give up meeting together, as some are in the habit of doing, but let us encourage one another..."
Apparently 2011 is not the only time in history when going to church was an easy habit to quit. What was important about church then is STILL important about church now. We 'spur' each other on. We offer encouragement. We connect with God. For some of us - and perhaps for all of us from time to time - church is the only time during the week we read the Bible, pray, or hear from God.
To me, going to church is kind of the foundational element of my spiritual discipline. It's NOT enough, but it IS essential. What I mean is that I also need to have deeper relationships than I can get by going 'to church'. I have to be in a small group where I can talk about me, pray for others personally, and hear from them. But attending church and participating in it is the rallying cry that we have in common, and it came with many benefits.
The Writer knew this. We should, too.