@Dipper_Dave - there is some truth in what you say on all points, but the park has tried various things over the years and it just hasn't worked financially, has performed inconsistently or has been more trouble than its worth (Winter Weekends, for one).
I won't quote line by line - but taking each broader point in turn.
Tourists - the tourist demographic is now very different than it was during the majority of the WGT era. People are coming for shorter stays with less tradition and several evenings at the Pleasure Beach has been replaced by a full day - or their Blackpool holiday has been replaced by a day visit to the park.
Other attractions late opening - this is true, but their ability to open late is because their cost base is so much less and the advanced purchase commitment isn't there. With an arcade for instance, if it's open you go in, if it's closed you go to the next one. The rotas required for staffing at the Pleasure Beach becomes infinitely more complicated with frequent late openings, for all departments.
Evening wristbands - I don't disagree some people would buy them, I just don't think there would be enough. Plus, even worse - I think some of the people who would buy them would be buying them
instead of an all day wristband, which is harmful to the bottom line.
Supplementary spending - Pleasure Beach has never been very good with food and merchandise vs. an operator like Merlin - I don't doubt there is money to be made, but I don't think they're leaving wedges of cash on the table.
Sambuca guy - he's a braver man than me, especially if he was taking a spin on the flyers afterward.