I want to buy new speakers for 50,000 and see it used for 30,000, what should I do?

Putting aside the issue of op's earnestness, you'd have to get EXTREMELY lucky to sell most 50K MSRP speakers for anywhere near 30K, even mint current models w/ transferrable warranty. 50K isn't the number you're competing with on most new sales. And those in the market for 50K+ speakers often want the paint to match their Porsche (etc). Private sellers can't always be trusted to pack & ship large speakers properly, often at a much higher rate than a dealer/manufacturer gets. And if that MK / version number increments up while waiting for the magic buyer, you're taking a much larger bath. The used audio gear market is tough right now, and selling speakers has always been harder than components. 

Please be considerate by not wasting our time.

What 'time' got wasted by the OP? We are mostly a bunch of semi retired/retired guys with deeper wallets, audio ocd and not a whole lot else going on in life...not too many Elon Musks around here working 18 hours a day right?

I purchased used Legacy Focuses and Signature IIIs after 20 years of stats. 

That's what I could afford for full range speakers without high power requirements.

Then I searched for my ultimate speaker I could afford (not the Von Schweikert Ultras I've heard).  During Covid there were a few remodeled VR9 SE Mk2s available from the factory for $50,000.  I ended up purchasing a updated, warrantied newly rewired pair with new Foundation (reliable) sub amps for $62,500 in mint condition from a private party who traded them in to the manufacturer's rep.  I am overjoyed with the purchase.  I stopped looking for speakers for my custom listening room.  I am looking for a similar or better quality speaker for my living room (my current Sig IIIs are painted black walnut) in pearlized white or deeper red tone like red cherry, rosewood, mahogany. etc. (the room is pink, gold and off white).  The cost to repaint is about $4,500 to $5,000 or find a wood pair (cheaper when available).  That's my story.  I am not considering market value or resale value.  

Shaking my head that people still don’t get it. A real gullible bunch of sods around here.

@deep_333 

Love your comments. Not all of us are retired, but I do admit I'm getting close with each passing year.  The 'wasting our time' comment was mostly based on the Ops lack of deciveness on whether he should buy new or used.  We all know that spending money on most audio components is never a good financial. If the Op isn't comfortable buying pre-owned speakers then put your 'big boy pants on' and buy new. No need to drag us into the Op's indeciveness.