Hamhock75,
1) Welcome to the team!

(okay, maybe my humor isn't great....what I mean is, welcome to the party of hams that are concerned about our transmitters' IMD!)
There's a wealth of info and data on this, including IMD scans of the FT-1000MkV in Class A (w/o any ALC action), 32S-3, K3, etc. etc...
I welcome you all to have a look!
And, yes....there is more to this than just the PA...
Tube or SS...good linear RF tubes or sweep tubes, etc...
The power supplies, the output matching, etc., all do play a role.
{and, ironically just 2 nights ago, talking with some friends on 80m....we discussed some "in-band" distortions that are inside the rigs passband, and the ability of the ANAN's PureSignal to clean them up as well....so, maybe if you all could design/implement a pre-distortion module for those old '560's, etc, you may breath new life into them! hi hi
} 2) And, yes Glenn....I agree that pre-distortion should be "mainstream" in a few years.
Although, how many years will it take to before pre-distortion rigs represent an over-whelming majority of the rigs on our HF bands?
That's a question where there may not be a definitive answer to?
But, my guess is that it will many, many years....maybe even a couple decades....
{as this isn't like the issue (incompatibility) as when the amateur HF community moved from AM DSB to suppressed-carrier SSB...}Predistortion will be mainstream in a few years. Icom's announcement that it will be turned on in the 7610 to support their new linear will help drive other manufacturers.
The processors in a modern transceiver are comparatively idle during transmit. That is a lot of available processing power for the pedistortion feature. Kudos to Icom that they foresaw this and included the necessary hardware connections to their processor chain.
- Glenn W9IQ
Maybe I'm wrong, but while I applaud Icom's move, as we've been waiting for this from them (and Flex, Elecraft, etc.) for over a decade now....I don't see the world of amateur HF comms changing to pre-distortion rigs for quite a while.

And, even after the new version of the 7610 and PW-2 are released, how long before other manufacturers release their pre-distortion rigs...rig/amp combos?
Now, even if these are all released quickly, how long before pre-distortion rigs become the majority of rigs on-the-air?
Again, I suspect a long time...
Even looking at the explosion of the '7300 onto the market as example, it's been over 7 years and while they sold >20,000 in the first 2 years, and double that since then....even if you double that again in the next 4 - 5 years, they'd still be a minority on-the-air...
Just saying that I love that Icom is doing this
(and, I have admired Apache Labs / ANAN for doing this years ago!), it's just not going to be all splatter on the bands will disappear in the next year or two.
3) Also, in regards to the new version of the 7610 and PW-2....I may be wrong here, but it appears that the 7610 cannot take in (sample) an analog RF sample, so while its software/firmware can be changed/updated to use the DSP processor to implement pre-distortion, it seems (as of now) that the only amp that can be placed inside the pre-distortion loop is the PW-2, as it will have a digital-sample of the amp's output and will be able to send that to the '7610 (via its ethernet cable?, etc.?) to allow the 7610's DSP to use that sample info?
Now, is this a precursor of what is to come from Icom?
Will they debut new rigs that will have analog RF sample inputs? Etc?
Maybe...
But, here again, this isn't going to mean that all the splatter on-the-air is going to disappear in the next year or two.

4) Okay, Hamhock75, et al...here's some more info/data for you all...
Have a look at these threads...
Perils of Hi-Power and some IMD scans https://www.eham.net/community/smf/index.php/topic,137162.msg1273707.html#msg1273707Better IMD Please (where you'll see that many have been talking about this for decades, and talking about pre-distortion now for > 10 years....and some saying a decade ago that Elecraft, Flex, etc. will have pre-distortion "soon")https://www.eham.net/community/smf/index.php/topic,79120.msg556484.html#msg556484Lost scans (tinypic!), but lots of data / numbershttps://www.eham.net/community/smf/index.php/topic,97093.msg1053647.html#msg1053647https://www.eham.net/community/smf/index.php/topic,101398.msg821031.html#msg821031Tube vs. SS, etc....https://www.eham.net/community/smf/index.php/topic,100600.msg809639.html#msg809639And, some posts on IMD, rig choice, etc....
https://www.eham.net/community/smf/index.php/topic,128776.msg1194749.html#msg1194749https://www.eham.net/community/smf/index.php/topic,128776.msg1195427.html#msg1195427https://www.eham.net/community/smf/index.php/topic,128776.msg1227431.html#msg1227431https://www.eham.net/community/smf/index.php/topic,128776.msg1227433.html#msg1227433Hope this helps with the discussion.
73,
John, KA4WJA