Probably the topic should be renamed as it’s not specifically down to old phones. Basically, it’s a lack of backwards compatibility which means that as Discourse development moves forward more people are being cut off from reading content held in Discourse and from contributing.
I realise that you are categorising this issue as “won’t fix”, which is fine, but be aware that the most important thing is the content. Your shiny presentation is nice, but if it gets in the way of me seeing content (and it does) then it’s essentially useless. And “buy an iPhone” is not really a viable solution for me.
But, fret not! I have found a workaround. I can view the content in Google’s cache! Most of the time I am searching for something and reading results. If one of the results is in a Discourse silo then I can’t read it directly (on my phone), but I can read a cached version. That’s all I need. If it’s interesting enough to follow then I’ll use my laptop. If it’s really interesting I’ll create an account and contribute (on my laptop, not on my phone). Obviously this is a non-issue for any other forum software, but I’m happy that I have an interim solution.
I am looking forward to the non-JS view. Especially as I browse with noscript all the time on my laptop. I hope you get it going soon.
Thanks.