Banks have the option of you physically going into the branch and identifying yourself with relevant legally backed forms of ID. That would not really work for most online companies.
Other methods which involve sending in copies of ID and/or letters signed by appropriate notaries would fail due to human engineering too because your average tech company isn't going to have people sat ready who are capable of accurately verifying this information.
The other problem is PR: due to the lack of another option the average person who is locked out of their account will instantly turn to twitter/facebook/any-where-else-they-can-post and scream as loud as they can that they've been mistreated by company X. Many other average persons will take this at face value without checking the fats and start avoiding company X, or worse bombarding them with communication in support of the inconvenienced user.