Thanks eleonorang for sharing your valuable ideas with community on this challenging blurred issue. I am throughly agree with you. However determining factor for this issue in translation industry is the customer demands as all we know and the translation industry has got a broad specturum of service providers (agencies, freelancers). A customer/client has a vast web of translators to choose, so a translator is unable to stand upon his way of determining charges. Even though the hourly based rates seem to be more reasonable, the customers or clients are prone to pay on the word count base (source or target). My point of view is that they feel uneasy due to the the fact that the translators might arange the translation time in the course of completion and thus they pay more. But as you say;
eleonorang we do not translate words, but meaning, perspectives, concepts, etc
An experienced and qualified translator translates not only ideas but also ideas, concepts, opinions and so on...But it's hard to make understand this perception for a customer or client. Because for a customer/client the cost is of great importance and consider always the the lowest price. However this method could be applied at some controlled big projects .
As for word count, with the same point of view a client/customer always cares about the text or whatsoever he/she has got. So I think it looks as if the source word count based rates would be considered for a long while...
By the way there are other factors for MTs like new words, repetitions, internal matches etc. These are the other factors influence the total price in terms of source word count based calculations.
That means in some ways translation is a little bit math in a sense