@Alaimo
As an outsider it's a bit depressing to see the 'of course this is the way academia works' attitude. I don't work in the UK, and the country where I work also has problems with precarious employment, but unlike the UK there are also quite a few researchers employed on permanent contracts here (I am one).
We can apply for funding for our own projects and if we don't have sufficient funding to make up 1fte we fill our time with other work that needs doing: teaching, admin, contributing to someone else's project, etc. It's not a perfect system and it requires quite a lot of coordination from PIs and departmental admin to make sure everyone has neither too little or too much work for their contracted hours, but it does greatly reduce the number of fixed term contracts. Now I think about, this is probably quite similar to the way research centers in the UK work as well: despite being largely reliant on fixed-term grants income they somehow manage to employ people on permanent contracts and make it work.
I definitely think that there can be changes made to how academia operates, including
some permanent research contracts (but I think there actually are some of these roles, albeit not many). The problem is that this will definitely not be possible for everyone because, in soc-sci at least, grant-income is not what funds the department - student fees are. Staff who want to research need to balance this with teaching and admin (which is what most of us do, to be fair). The issue comes when someone does receive grant funding and needs research-support in the form of a post-doc or PhD. In my field (where big grants are rare, even for profs), it's not financially viable to have permanent RAs who don't teach. We have a few post-docs and Leverhulme fellows but those are also fixed term and I can't see how they can't be. A big big problem is also the huge increase in PhD students, including those who self-fund. The majority of the hourly paid work in my dept is done by PhD students. How can a student become a permanent staff member? I think their conditions are often pretty shit and need to be better but the harsh reality is that there are nowhere near enough jobs in the sector for all to get one. Again, this is something that cannot be changed. It's an uncomfortable truth that more senior academics use PhD completions as a way to get promoted, even though there is little hope of most of them getting a job afterwards. Reforming academia would mean putting a stop to this. However, most senior academics won't like that because it means they can't get relatively cheap work on their funded projects and that they will struggle to be bought out of teaching.
UCU's attitudes seems to be unis are all rich and can afford this, when the reality is far more complex and not simply in the control of the institutions. This is also why opening up membership to PhD students is questionable because we do not 'stand together'. In fact, a more apt description is that senior academics stand ON PhD students to get ahead. Pretending that isn't the case helps nobody.
And while there are other countries where precarity is not as widespread, in many of those (eg Germany), entry into academia is incredibly competitive and the vast majority of those working on precarious contracts here wouldn't have a hope in hell of a foot in the door over there.