@Instography, hey dude you've gone all existential angst and pessimism on us. Relax, it's only politics. We're not deciding if someone (or a group of folk) will live or die. We're deciding how we want to be governed, the constitutional set up. That's all.
Much to be optimistic about (subject to various caveats, as ever).
As for socialists in the Scottish Parly, there are two Green MSPs. The Green party is pretty much the home of the left in parliamentary politics in Scotland these days, though the party includes a spectrum of views. Greens are not wedded to coal, steel and heavy industry like the old left were. There are new ideas around, but with a familiar ring, different ways to redistribute wealth, create a more equal society, and trying not to completely wreck the planet while building the future.
Regarding the 1970s, during that time I lived as a small child, in an Edinburgh council estate, and then, in a small mill town in East Lancashire. Looking back, I think it's true that things changed in the 1970s, mainly the impact of consumerism and the growing obsession with owning property. I imagine this started even earlier in the south of England. (Hanif Quereshi's 'Buddha of Suburbia' is a good semi-autobiographical account of this time: read the book or watch the TV series).
Thatcher coming to power was part of a process that had been going on for some time, that government accelerated trends in society, and pushed the polarisation of different economic and political interests. With Thatcher we saw a Tory party much more ruthless in the domestic sphere than previous post-war governments, more ideologically driven (by a belief in Monetarism and deregulation), on top of the old class interests. One of their first acts was to abolish capital controls: this let wealthy individuals and companies salt their investments away off-shore tax free, and consequently investment in industry dried up. That, and spiralling interest rates (designed to tackle inflation, see Monetarism) destroyed much manufacturing in the UK.
There was also a slightly desperate harking back to imperial grandeur, banging the war drum, hoisting the union jack, sending amongst others, a young Keith Brown into battle against Argentine conscripts in the Falklands. By that time the Labour and Liberal parties had split and the short lived SDP project vainly attempted to take the centre ground of politics: "breaking the mould" they called it. This divided opposition, plus a trade union movement reeling from industrial collapse in the early 1980s, was what allowed the Tories to stay in power for so long. That dominance, and the social and economic changes driven through by successive Tory governments, was the real mould breaking: it recast New Labour in its own image, and set the economic and ideological conditions (the "legacy" we would call it these days) of what the Blair government would inherit.
So one can say that the left was in decline, and conservatism on the rise in the 1970s. However the ideology and policies of the Thatcher government created many of the problems we now face: deregulated mega banks who swallowed up smaller competitors through mergers and acquisitions; loss of manufacturing industry; loss of social housing stock; rampant property price inflation; corporate tax avoidance; massive consumer debt; etc.
In fairness New Labour did try to reform some of this around the margins, reversing some of the most iniquitous, totemic aspects of ideological Tory policies: including the quasi-colonial governance of Scotland, Wales and Northern Ireland. They did not fundamentally change the economic policies though. The "third way" was effectively Thatcherism with a small 't', a friendlier handshake and a softer tone of voice.
Phew, didn't quite mean to go on quite so long. None of this will come as a surprise to many of you who lived through that time. I do think though if we want to understand why we are here and now politically we need to look at what brought us to this point. To some extent, devolution in the late 1990s has allowed Scotland to tread a different political path from mainstream UK politics: the rise of the SNP, and the presence of smaller parties (especially in the early years of Holyrood) is testament to that, whether 'we' voted for them or not.
If we look at that relatively short history of devolution we can see that there are new, or at least different possibilities that could open up following a Yes vote. Some folk find that prospect unnerving. Personally I'm much more worried about what might happen to politics after a No vote.