As has been mentioned, if you use italics to indicate thoughts, you rarely need to use "thought" as a tag. It's redundant. But there are times when the tag might be useful or necessary. For instance, if you want to add an adverb to the tag, to convey a certain tone to the thoughts. Or when you want to combine both a thought and an action. An example of each type below:
I don't listen to audiobooks, but I have sometimes wondered how the readers make direct thoughts obvious when there are no tags. Still, I don't think we want to pepper our manuscripts with thought tags to compensate.
I haven't consumed many audiobooks either, but it's my understanding that a good reader varies the tone of their voice and rhythm slightly for different characters. That helps get untagged dialogue and thoughts across without confusing the listener.
I don't know how it works with the type of e-reading that is done with a "computer" voice reading from text, though. I'm guessing the listener may have to back up and repeat some passages to understand them. Or maybe the listener gets used to a given author's style after a while.
I've noticed that tagging and filtering seems to be coming back in vogue though, at least in SFF books written in recent years. So maybe editors are telling writers do do more of the things we've been telling each other
not to do for the past couple decades (at least). Perhaps the audio market is the reason?
Or - use a physical mannerism to convey an emotional state:
He smirked. The dude is afraid I'll bolt for the wall again.
I dunno, that would actually knock me out. Since we're in the head of this person, I'd wonder how he was aware of smirking specifically (unless he is doing it deliberately to be rude). I think there are times when the tag works fine, though, as with Beth's example.
I'm not sure "he thought" would be a filter in a case where you are directly representing what the person thought versus summarizing it.
I never knew you, she thought. (a tag)
vs
She thought then that she'd never knew him
In the latter case, it often works better (imo) just to write something like "She'd never known him."