There actually are shorter-form therapies derived from psychoanalysis that do have manuals, and studies purporting to show their effectiveness. The point wasn't

There actually are shorter-form therapies derived from psychoanalysis that do have manuals, and studies purporting to show their effectiveness. The point wasn't that these therapies are all that great - they probably aren't - but that measuring psychotherapy is a methodological ball of tar and prone to confirmation bias.