You're turning the means of grace into works of salvation, but miss the whole picture. When you mention them in that way, you turn them into external works and miss that through the Word and Sacraments, God does something to you. Consider the self-righteous Pharisee who remained unconverted though he always searched scripture and attended to God's commands.
All that you've proved is that we can commit spiritual suicide and fall away from grace. But that is not the same as choosing to believe in Christ! It's kinda like life, God grants it and he can take it away, but I can also commit suicide. But no matter how strong or determined to live I am, I can still die at any moment.
I don't believe I've committed spiritual suicide, for I still recognize that it is Christ who is doing the doing in the sacraments. What I reject is the idea that it isn't a discipline to allow Christ to do that work. I've had enough days where I haven't wanted to go to church, or wanted to read Scripture or wanted to confess my sin to know that none of them are an entirely passive experience. At the end of the day I have to decide to receive God's grace or I don't receive it. Put another way, I can only receive what I choose to receive. Does God do the sanctifying through the sacraments? Of course. But there's no sanctifying if I don't decide to receive Christ through His means.
As for the Pharisee, his sin was puffed up knowledge through reading the Scriptures; not failing to recognize that it is God working through the Scriptures that matters.