The reason why it isn't any easier having the Holy Spirit to helps us obey and keep from sin is because God hasn't taken away our free will. The Bible says that we can grieve the Holy Spirit, showing that it is possible to resist His work in us. This shows us that the Holy Spirit (and God the Father and the Lord Jesus) will not ever force us to do anything. We must be willing to submit to God in order for Him to work in us.
The Lord Jesus showed that it is possible to fully submit to the Holy Spirit which should be a great encouragement to us.