Weakest link is the place to start.
But if I had to choose, the source is the more important foundation than speakers. A $10K source with a $5K amp will sqeeze every drop of performance out of a $2K speaker and make it sound like a $5K speaker, rather than the other way around, as long as that $2K speaker is not randomly chosen.
Example I have heard:
Furutech passive power conditioner - Melco S100 with LPS - Lumin P1 - CODA CSiB - KEF LS50 Meta - Audioquest Diamond, Yukon, Coffee, Monsoon and Rocket 88 cabling.
Don't love KEF speakers but this setup taught me at least those particular KEFs can sound superb given a clean, powerful signal.