Question

Why was Barnabas unable to work as much as he would have liked to?

Answer 1

Answer:

Some people might think OP's original text using the Perfect Infinitive (to have seen) is more "logical" because it more explicitly echoes the past tense element of would have liked. But note this from Garner's Modern American Usage (2009)...

would have liked

...should invariably be followed by a present-tense infinitive — hence would have liked to go, would have liked to read, not ✳would have liked to have gone, ✳would have liked to have read

Answer 2

Answer:

Nonsense answer . what's wrong