In dayenu, we say that at each level of what God did for us, it would have been enough. Since we didn't get the Torah until one of the last stages, this seems incorrect, since of what value is money, wandering in the desert, and all of the other details if we don't have the Torah?
The answer is that we need to be grateful to God for each miracle that we received, and that at each stage, we owe praise and thanks to God.
Also, in one sense, we already had the Torah (in some version, even though not in the form in which Moses/Moshe wrote it later).