I wouldn't take the wilder parts of Corbyn's manifesto too seriously. If he wins he will have to make some running to stop his party from splitting, which means a compromise with the NuLabour MPs. Between Corbyn and the people he will have to compromise with, the Labour party will end up pulled back to the left where they should be, but not as far left as Corbyn and many of his supporters would like.
Or you could carry on with the situation where Labour is being reduced to Tory Lite and no real opposition exists. Clement Attlee would be ashamed of the modern Labour party. Attlee took over a bankrupt country in 1945 and built a social welfare system and the NHS from the rubble. They also gave India her independence and welcomed in immigrants from all over the commonwealth to make their home in the UK.
The current Labour party is in a country which is the fifth richest in the world, and opposing a Tory party more right wing than any of Thatcher's governments, and they abstained on the welfare bill because they didn't have it in them to oppose austerity!! They have failed to nail Cameron's testicles to the wall for what he did in Libya, failed to speak up about the spiteful Tory campaigns against immigrants, benefit claimants, the disabled. They engaged in tactical voting pacts with Tories in Scotland to try and keep the SNP out, (for which they will probably never be forgiven by the Scots), stood by silently while the Tories encroached on civil liberties in the name of anti-terrorism, and have clearly no clue what they're talking about when it comes to policies on tax evasion and corporation tax. Basically they're useless as an opposition in their current form. You might as well have Corbyn as Labour leader because even if he is unelectable as Prime Minister, all his opponents are too, and at least he would make a strong opposition leader.
I agree with almost everything you say, speedy cat.
Labour are failing in every department, seem conflicted, and are willing to say anything Tory-like in order to win back voters who no longer trust them. And I agree that the current batch that are standing don't have any real chance of winning anything that counts. But what I'm not so sure about is that Labour should just give up, and back someone who will turn the party into what most likely be the best protest movement in the world. If any of the others have an even slightly better chance of actually winning power for all in five years, and that includes the left as well as the Tory-lite, then Labour should go after that faint hope. The time to give up is not now. Labour should give itself the best chance of winning power, however slim that is, and then once in, set itself to work on implementing some good policies in amongst all the Tory drivel that necessitates an election victory these days.