Will decent speakers always out do headphones?

Really depends. You should tell us about both setups.

There is a lot to be said for cross-mixing of headphones to give a fuller sound, but you should be aware too, are you listening with your body? Maybe your speaker experience is through your skin, not your ears and that will never compete. 
But, in terms of what comes through the ears, headphones can excel at giving every little bit of nuance, because you loose nothing from room acoustics.  Getting that same level of detail can be a lot harder with speakers and rooms.

Best,
E

I get what you are saying regards to detail. I could definitely hear tiny nuances such hand claps etc (in live recordings) that might not have been as pronounced through the speakers but as far as the general sound size (does this make sense?) its not the same. Speakers make the music fill the room. Headphones filled my ears but not in the same way. Maybe just need to get used to the difference. Headphones are the Sonus Faber Pryma. I have tons more hours on the speakers and only a handful on the headphones which may be a big difference also.

I was just thinking about the subject yesterday. I have good headphones and have had some pretty serious headphone amps, DACs, etc. However the experience is just different. Yes, with headphones you may hear some detail that was less noticeable through the speakers. However, it's just different. I also agree with Erik that you also hear with your body. When you don't feel the music though your body, the experience is not the same.

A headphone amp with cross feed may improve your headphone experience if you have a preference for the sound of your speakers. However, you'll never get the same "feeling" from headphone.

Plenty of people have a preference for the headphone sound. I'm not one of them.....

Tele, again, please give us more details. Heaphones, headphone amp, and what speakers?

I also want you to think again, are you feeling the sound through your body, or is it a sound stage issue?

This will help you I think:

https://en.wikipedia.org/wiki/Crossfeed

No objective answer for that. I don't like listening through headphones, no matter how good they are.