I had several formative experiences earlier in my audiophile career that enforced the importance of the speakers. Mostly this had to do with hearing great speakers with meagre electronics. The first experience with Quad ESL 63’s blew my mind, and they were hooked up to a tiny, cheap Dynaco ST-70, with cheap speaker cable/interconnects. I heard the Waveform Mach 17 speakers (at the time) blow away practically every audio system I’d ever heard (and I’d heard scary-priced systems by then, most of what was available), and those speakers were running on some cheap amps (Kenwood if I remember), and bought-from-home-depot level cabling (John Otvos demoed them, he did not buy into the idea of expensive cables/amps).
When I first got my Quad ESL 63s I had to use my girlfriend’s Harmon Kardon integrated amp and cheap CD player for quite a while and yet the sound was incredible. Yes I upgraded CD players, amps (to CJ tube gear) along the way, but those were incremental improvements relative to the huge difference made by the Quads over other modest speakers I’d heard and owned.
Over the years, especially when my high end audio fever was at it’s highest, I heard systems put together by audiophiles who ranged from "everything makes a difference" - huge expense for cabling, raising them off the floor, crazy amp prices, every component on isolation etc - to systems owned by more engineer-minded audiophiles who dismissed high end amps/cables/Dacs and concentrated on the speakers and acoustics. Both "sides" could produce incredible sound (though the more practical audiophile set ups costing much less, usually).
So for myself, I’m a speakers-first guy, amps second (I like tube amplification), everything else far below that (probably DAC next).
I’ll spend some good money on amps, like my CJ monoblocks, but with the recognition I’m chasing smaller sonic differences/improvements than I get with speakers.
I have various speakers, including Thiel 3.7s. I feel the Thiels are at a point where I start paying much more for incremental differences in speaker performance. They are powered by CJ premier 12 monoblock amps, music streamed to a benchmark DAC. Stock AC cables all around, 10-gauge Beldon speaker cable (large gauge due to 30 foot length from amp to speakers). Sounds incredible, and I think more impressive than many far more expensive systems I hear elsewhere (in fact I’ve been shopping to see if I can find a replacement for the big Thiels, and far more expensive systems I’ve auditioned have left me less impressed than my own set up. One friend is a high end audio reviewers and he has an unmentionable dollar amount worth of cables, usually high end amps, amazing sources, and superb monitors - but I think my system sounds significantly better. Thiel 3.7s are far better speakers (and I have great room acoustics) and they make more of a difference even when used with much more modest gear leading to them.
That said, I have heard certain gear that seems to produce exceptional results when hooked up to many different speakers. My little classic Eico HF-81 has an absolutely magical tone and tends to make almost any speaker hooked up to it sound more ravishing. But it can go only so far in breaching the difference found between speakers.