Idiom usages are complex issues that have been evolved over time by the speakers of a language and they transcend the frontiers of rules and regulations. Just because a superlative degree takes the definite article 'the'' for the uniqueness of the issue, we should not think that the word 'the' cannot be used for the comparative degree and positive degree.
Let me give some examples.
The sooner, the better
The poorer, the more blessed
The more one practices, the more confidence one gets
The more the money one has, the less busy one becomes
The warmer day, the better the mood
The less said about it the better it is
Tom is the taller one of the two siblings
Who is the more naughty, Tom or Jerry
Theresa is the more likable person
Therefore, in the comparative degree, you don't always skip the definite article or compulsorily use the word 'than'