Hello! Great question!
In the first question, in natural English, you wouldn't use either. You would say "Now a days, drivers show "very little" respect for traffic rules. Meager and scant are most commonly used to define material things that you have low quantity of, not usually emotions or feelings.
With the second one, you could use either one, but it would depend on what your talking about.
To "like" something is to say its something that you casually accept, and it isn't truly important to you. For example, you "like" ice cream, you "like" television.
When you "value" something, it has great importance to you. You "value" your family, you "value" you education, you "value" learning English.
Hope this helps!!