More money toward better speakers or a better DAC?

I have speakers that sound right to me in a room meant for such speakers and treated the room to my liking.
My old DAC served me   A Bryston BDA -1.  The AM DAC improved the “air” around notes, added soundstage height and depth, and improved tonality. Resolution remained the same which was always good. 

Sorry, my BDA served me well. All within a system that retailed at about $15K. 

A DAC is a worthwhile upgrade. I am reviewing currently a $5K DAC that reveals the improvements over the years (about 3 years) in DAC performance. The change to performance is as strong as any preamp, amp or set of cables. Imo, if you are very serious about advancing your system and listening, it is defensible to upgrade the DAC every 3-5 years. If I did not review I would question the reports of how much DAC improvement there has been. But, the results are overwhelming, undeniable - and that's based on building many rigs for comparison, not just one. In the current comparison to the 3 year old DACs the difference is striking, imo well worth upgrading.   

Speakers are limited by the upstream electronics, so you can get different, and even "better", but don't expect a speaker change to magically make the components leapfrog their absolute limits. The components will not magically morph into upper end gear. Do speakers if you have a lower end set and wish to elevate substantially within the limitations of the components, or if you want a sea change to a different genre of speaker. 

Speakers... All day.

DAC technology fools/tricks people into believing the more number crunching going on results in better sound. 
Don't drink the mainstream Kool-Aid.

Speakers first... And if you get efficient enough speakers, then that opens the door to single ended triode bliss.
Or whatever class of amplification tickles your fancy.  I'm just sayin. 

after taking in all the helpful comments above, I remain perplexed but closer to a next step. 
I have b&w diamond speakers and a solid amp.  a dac will be helpful.  Bluesound node 2i dac confines the music.  
A new wrinkle above is learning the longevity of a dac can be short - 3 - 5 years? What causes a dac to deteriorate so quickly?
I believe it ain’t easy doing a great job converting digital to analogue.  
So many dacs out there and any choice requires a leap of faith.  I originally started out liking the chord tt2 and now believe this will be a great choice.  Absolutely amazed how many dacs are out there, a choice is soooo difficult.  
I liked the bartok, but it seems very overpriced.  The David seems excellent but tough to tame after purchase. I like the m scaler, which seems overpriced. And tt2 seems overpriced too.  But I want a good dac and it better last a long time.
All about feeling comfortable with a purchase.  There appears to be lots of good choices.