When the WT says you can't earn salvation, they mean that without the
gift of the ransom sacrifice all your works would be useless, but
because of that gift, your works now can show that you are worthy of
salvation.
So salvation isn't earned; it's a gift.
But that's like saying that your paychecks aren't earned; they're gifts.
Why so?
Because
if your boss hadn't given you a job (something he/she was under no
obligation to do), he/she wouldn't have to pay you anything no matter
how many works you volunteered to do for him/her; therefore, your
paychecks are gifts.
Isn't WT logic amazing?
On JW dot org, the WT makes the analogy of a rich man offering an expensive gift if you come to a specific place at a specific time to receive it.
Even though you have to do something to get it, it would still be a gift.
But that analogy is false because it's nothing like the WT salvation system.
If the rich man made you come to 3-5 meetings a week and go door to door promoting his literature the rest of your life, that would no longer be a gift.
It would be wages.