It would have been perfectly possible to make Alba go away after the election. New parties that suffer electoral setbacks on their first outing are vulnerable to total collapse, as Change UK demonstrated two years ago. But Change UK ceased to exist largely because a number of the key players found an alternative home in the Liberal Democrats. If the SNP wanted a similar exodus from Alba that would eventually lead to the party ceasing to be viable, the way to achieve that would have been to smother Alba with kindness. They could have said "we have shared values and objectives, your poor result gives us no pleasure, our door remains open to you". Instead the SNP have treated Alba members as scum who have no place in civilised society, let alone the independence movement. The latest manifestation of that is Pete Wishart's new "blog that everyone's talking about" (sic), which gloats at considerable length about Alba's low vote share and leaves little room for doubt that he viscerally despises Alba members. To use Ian Davidson's immortal words, the likes of Wishart, Stewart McDonald and Kirsty Blackman want to spend their time "bayonetting the wounded" rather than healing the rift. That destructive attitude is producing the natural and rational response: "if we have no home in the SNP, then our home is Alba, and we're going to make it work".
The point Alba-haters are missing is this: to try to jump from 2% of the vote to 5% is not really all that ambitious, and that's all Alba really need to do at this stage. If they could get 5% of the first preference vote in the local elections (or perhaps even 4%), that would be enough to build up some credibility as a serious player as long as they get a few councillors elected as well. And given that some of their candidates will be incumbents who have had time to build up a personal vote, that's not beyond the bounds of possibility. With a half-decent local election result, they would then force their way into the conversation about which parties are entitled to TV and radio coverage under Ofcom regulations. The SNP would constantly have to worry about losing the votes of the most radical independence supporters, in a way they simply haven't in the past. That's the scenario Wishart's own handiwork could be helping to bring about.
Incidentally, because Wishart lists a series of largely spurious "reasons" for Alba's setback, it's worth pointing out one much better reason that was discussed at length before the election but not so much afterwards - the Electoral Commission's refusal to allow the Alba logo or description to appear on the ballot paper. A lot of people were struck by how hard it was to find Alba, even though they were close to the top - they really didn't stand out at all. That's where it might have been an advantage to have a "Ronseal" name like Independence for Scotland - because the name itself would have doubled as the description. I'm not suggesting that the Electoral Commission's decision swung the balance between winning seats and not winning seats, but I do think it may have reduced Alba's vote share somewhat.
As for Alex Salmond's future, I'm just going to wait and see what he decides - there's no better political tactician than him, and whatever decision he makes will probably be the right one for the party. I can see the argument that a new leader would remove the 'distraction' of every single BBC interview being an attempt to rerun the trial, but I think there's a strong counterargument as well - the grass doesn't always turn out to be greener on the other side. Every time Nigel Farage has stepped down as leader of UKIP or the Brexit Party, that's always been followed by a slump, because Farage was not only the party's main electoral asset, he was also the glue that kept the whole outfit together. Although Alba is a very different party from UKIP, and Alex Salmond is a very different politician from Nigel Farage, the same principle could apply.
That said, Alba are blessed in having two MPs (including a former Justice Secretary) as credible alternative leaders, so it's not impossible that a change at the top could work out - but I hope it's all thought through very carefully before any rash decisions are made.