Own many mid-game speakers or a few end-game speakers.

All tweeked out "Burmester 961"s floor standers.
Every time my front-end improves, e.g. amp bias readjustment, cable differences, x-over Mundorf bypass caps, pair selected new carbon AUDAX 5½" midrange drivers..., they do play along and show the difference / improvement - and this since their 1996 purchase!
It still always amazes me how they can do this!?! 
To this end I'm now too scared to even consider any replacements.
M. 🇿🇦 

This is a tough call.  I have two pairs of speakers I am perpetually swapping between.  I just had a blogger over to discuss systems and he is in sort of the same place.  

He is looking at upgrading to MBLs which are such cool speakers but would miss "cone and dome" sound on occasion.  His view was one big time speaker (like MBLs) and some less expensive speakers that deliver different sound.  

It's an approach.  One comment he made was that with two large speakers (MBL and say Magico) he would never swap because they are just too heavy.  

no right or wrong approach. it’s a hobby and there are no rules........except being true to the music reference in your mind.

personally i view optimizing my music playback reference efforts start with getting the best single speaker system i can that is properly sized for the room i have, and then working to get that speaker system to be it’s best.

i happen to purchase a twin tower fairly expensive speaker system. this was after 17-18 years of serious listening in a dedicated room, and visits to many rooms and audio shows. so it was not a casual decision. i’m not techie enough to attempt a DIY approach, and have no reason to doubt it’s validity to attain high performance. i'm skeptical but open minded that a much less expensive speaker system could compete head to head. it could happen.

my personal view is that the room<->speaker relationship is so intertwined and synergistic that having multiple speaker systems used in the same room would be an anchor holding you back, and in no way a positive. unless it’s a test or trial period. but not as a permanent approach. but that is just my own opinion.

if you want to have multiples of things to play around with in a single room, then it should be amps or turntables or something not as set-up critical as speakers. it can take years to get speakers to be their best. and until the room<->speaker room synergy reaches maturity you have no way to really know what the speaker can do.

Errr, hype=hyperbole=exaggeration=something that, by definition, you shouldn't believe.  Jus' sayin'.

I'd want to mix it up with at least 3 different genres of speakers. First, a set of panel dipoles, Magnepan 20.7 or 30.7. No box can ever offer the spaciousness of a panel. Next I'd go for a mid-size full range with great dynamics, Wilson Yvette or a Focal, Revel Ultima, there are tons of $25-30k range that are incredible. Finally, I'd want a pair of mini monitors like a KEF, B&W, or Harbeth. Shortlisted would be a horn based design, Klipsch, or vintage Altec 604-8G in a 6ft3 cabinet, maybe - if I had a proper tube amp to drive them.