Yes, I agree about the license switching multiple times being the biggest issue. It's similar to to franchise stops and restarts of the DC movie universe. How many different actors will play Batman during our lifetimes? The comics aren't that different with whatever Crisis doing a reset, New 52, Rebirth, All-In, whatever.
However, Todd's choice to change the line to 7" is the most problematic and what made the Mattel and McFarlane lines the most incompatible. I'm betting that was a conscious choice to try to make people start over. It's something that I'm incapable of forgiving and why I've truly never "bought in" to McF despite owning hundreds of their figures. I've bought at least one version of every character that he's done, but the vast majority have never been opened - because part of me knew that I likely wouldn't be keeping them. The only ones that I've opened were from Collect-to-Build waves (which he mostly abandoned) or came in damaged packaging.
I'm not making any decisions on collecting DC post-Todd until I know what Mattel plans to do. They could do something wildly unexpected and go with a totally different scale like 3 3/4", 4.5", 5.5", whatever... I'd be completely out at that point. I highly doubt that they would actually do something like that, but we don't know yet. The idea of Todd switching to 7" back at the time seemed insane also.
The disparities in the lines done by DCD, Mattel and McFarlane are the single biggest reason why anything DC could never overtake Marvel Legends as my primary line. Hasbro/ToyBiz has given me a mostly compatible / consistent toy franchise for 25ish years. It certainly hasn't been perfect by any means, and I have my gripes about that line as well - but it has still been more consistent than it hasn't. (Although even they tried to change the scale to 3 3/4" at one point). Just like with their movies, DC can't stick to any type of long term plan with their collector action figure line either - and that's likely frustrating for everybody. Similar to
@Atomic Knight, my collecting desire is for the deepest world building and character selection possible within my collection and stops/starts and inconsistency across the product make that harder than it should be.
I don't at all disagree, and I do have to wonder- if/when a company makes a big swing, like Todd switching to 7 inches from 6, why the company that gets the license after doesn't at least attempt to play ball? If the line crashed and burned, that would be one thing, but since there's obviously been success, and you're right- most folks won't just want to start over from scratch, it surprises me that there isn't more of a concerted effort most of the time to get something at least a little closer to the previous product, and maybe slowly change the scale over time, if at all.
Don't get me wrong, I know that 6 inch scale is generally considered to be the most "desirable", but in this day and age where we're used to all kinds of scales, even multiple scales in the same line, I think the
need to stick to 6 inch is less and less. There's pros and cons to any of the scales, but switching up the scale after years and years of customers buying one thing is only gonna piss them off. Yeah, Todd did it too, obviously, but now that fans are used to 7 inch, switching back to 6 feels odd to me too. It's totally possible that Mattel can pack the same amount of articulation and detail into a 6 inch figure, but the question is are they going to? They're a bigger company with a bigger bottom line and more people to please, so they're looking to save wherever they can. In doing so, ignoring what came before just to give people what you think they want (or worse, just forcing them to accept something) never works well, whether in figures, movies, etc. Obviously with businesses like this, you kinda have to take the reins and make a decision, or else product would never come out, but I digress.
I know people are always going to buy figures, especially DC figures, regardless of scale. But I do think there's generally a breaking point for a lot of collectors, especially as more and more characters get done. At what point are they unlikely to support a new line at all if doing so means the product will stand out for all the wrong reasons? Like you said, with the movies, people became less interested in seeing the new DC stuff because they knew there was a reset coming, so what was the point getting invested? With scale switches, the only time it really works is if you're a character-specific cherry picker. Me, for instance, with my Scarecrow stuff, I'm cool to get him in any scale and style, but if I was looking to buy new stuff, say a McFarlane Batman Begins figure to put in my old Mattel Movie Masters line, that would be silly.
Anyway. I don't know where I'm going with this. I shouldn't be allowed to type on little sleep. Point is- scale switches are annoying and no one likes them, but I do think that a lot of the blame is on the company for not wanting to honor what came before and help fans integrate the new product a little more seamlessly.