$7000 preamp vs $700 receiver - Is the difference THAT significant?

Tube gear sounds better than Solid State. You can get Burmester SS gear and it will be very smooth and resolving and dynamic. But it will not warm your heart. 
There were excellent companies producing tube gear. THE FISHER, SCOTT, MARANTZ, SANSUI, LUXMAN ... BUT McIntosh is the only left producing it. And it was technologically leading.
I can not afford McIntosh tube gear and I am very happy with my THE FISHER tube receiver as I am into vintage tube gear.
From a vintage gear tube point of view, there is nothing more beautiful than a PRECEIVER with a magic tuning eye and a nice stereo tube power amp with 35 watts to juice it.
This leading edge gear will provide you with a very solid stereo image, muscular sound and a very high sound to noice ratio.
If you want (almost) the same level go with a 35 watt tube receiver or used "modern" (1980) tube gear from Sonic Frontiers.
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And receivers can sound really good - vintage tube receivers that is.
 

Update: I have a piece of gear inbound.  I actually made a bid on a C52, and after talking with the dealer who was re-selling it, was introduced to some other ideas.  The one I settled on, PrimaLuna EVO 400... should arrive today.  

After digging in... and seeing that SandyG himself used that equipment to demo the speakers I have (Triton 2+'s) ... I figured: "how could I go wrong?"

From all I've read, I'm sure I'll be thrilled.

Depends:  Are you running the $700 preamp into the $700 receiver?

I would hope so .If there isn't I spent a ton of money. Dam.

Interesting comments.  Have bluesound node 2i and replaced it with a separate dac and roon nucleus.  Bluesound is a poor streamer/dac.

I may get the C1100 mcintosh preamp.  But I don’t plan to use the phonostage part of system, wasteful.  All this vs spending entire $14k on C1100 or using funds toward a preamp without a phonostage.  C1100 is very nice but it does use a lot of space.