The first one is correct:
- The ruling class is incapable more than unwilling to pursue the public interest.
You could, however, flip ‘more’ and ‘incapable’, to make the sentence clearer and highlight the contrast between ‘incapable’ and ‘unwilling’ thus:
- The ruling class is more incapable than unwilling to pursue the public interest.
The second is incorrect:
- The ruling class is incapable more than unwilling of pursuing the public interest.
...because you can’t say that someone is ‘unwilling of doing something’. You need to say ‘unwilling to do something’, to be idiomatic.
When you have two adjectives, you use the preposition that matches the word nearest.
There’s a missed out but assumed invisible ‘of’ after the ‘incapable’. But this would often be left out to allow the sentence to flow.