Thanks for clarifying. I think the issue with relays blocking spam is you only get the benefits if you limit yourself to those relays. I don't think network islands are good for Nostr in general and for their users in particular.

I think that there are many other ways in which relays can provide value, like being reliable, offering data retention services, not banning you for your speech, etc. 

Ultimately relays are back-end databases and there's only so much coin someone is willing to fork over that. A model where relays are free is feasible, they're very light on resources and there are examples from the past where this has worked, see large IRC networks. IRC servers play no part in filtering channel content either. 

 Your assumption is wrong. You can use the spam blocking relay for some things and look at spammy relays for others.  You can just have both amd get the best of each for whatever context makes sense.  

 Be specific, can you still see notes from spammy relays or not? And if you can still see them, are you still getting spammed with unwanted notes or not? 

 Sure. You see the notes from spammy relays but only when you want to. 

For example, you can use a client like get-tao.app to look at the spamiest notes possible (from anon accounts, the only barrier to post is POW) or you can use your insular ingroup client when you only want to talk to fellow turkish rug enthusiasts.

Easy to imagine clienta that would allow you to seamlessley switch between the two contexts 

 Ok, so we're agreed that you do have to be isolated on the insular group in order to avoid the spammy notes, but you're proposing that being able to easily switch to spammy relays solves for that.

I suppose when the turkish rug enthusiast relay goes down, we take a break from talking about turkish rugs? What if it never comes back?

And why can't both spam and communities be solved at a client level to achieve the same thing? 

 The group can have multiple relays, obviously. 

 They could too, more options is better