Personally, I might have preferred that they excluded non-commercial and non-modify variants but, as a practical matter, those probably needed to be included.
TBH, I'm not sure why most people who don't want to pay wouldn't just license their photos CC--what percentage of Flickr users are going to sell photos to any meaningful degree--but maybe increasing CC licensing is part of the intent.
[ADDED: I do agree that many people have a reflexive desire to control things that are "theirs" or at least to keep others from making money off of it. I'm just saying that if many/most of the people who want to use Flickr for free thought about it rationally, they'd come to the conclusion that they're not really losing anything by licensing under CC.]
After all, people can already contact you and ask for your permission to use a photo (for a payment or otherwise). Organizations have done it with me lots of times. (In my experience, many want to get explicit permission even if something is licensed under CC.)
To be clear, there's absolutely nothing wrong with reserving all your rights to something you've created. But it's not open source/Creative Commons if you do so.
I was responding to "why most people who don't want to pay wouldn't just license their photos CC" and the following bit - wanting to be paid isn't the only reason not to use CC or any other open license.
Your criticism should point to CC itself then. The reason to use it is that it takes a few bytes to express your license which would otherwise a lawyer to consult you. And on the other hand a potential user immediately understands whether the license is appropriate for her.
Or what If I want a gallery to be able to print my pictures and show it as is, again because I put in a lot of thought and work into the coherence of my artistic vision, but I don't want video artists to chop it and reuse it in a weird setting?
I think those are legitimate use cases for a license.
From their cameras popularity graph (https://www.flickr.com/cameras), I think the popularity of Flickr has died off with Instagram and all the various social networks. The most popular camera phone on there is iPhone 6 (2014). For point and shoots, it's the first generation RX100 (2012).
For me it was because uploading a photo to Instagram was a trivial process (launch app, pick photo, type words, done) in an app that felt nice - Flickr's iOS app was awful. That combined with Flickr's incessant need to dick around with the UI/UX and break things lost me pretty quickly. This year I won't be renewing my Pro.
I'm actually a bit of two minds about comparing Flickr with social media sites like Instagram. Certainly, casual photo sharing is far more popular on those sites. On the other hand, I'd have to be convinced that a single site can really function as SmugMug or Flickr do for people who self-identify as prosumers while at the same time also being the preferred site for the typical Instagram user.
Now, if all Flickr network traffic (ads, content, images, resources) were to be exempt from impacting Verizon pre-paid data plan bandwidth allowances, that might almost be something.