Having actually been to Dreamland, I think the current system is the correct one.
There are parts of the site which are free to enter then pay for facilities, and you can buy an ice cream, drink, pizza, visit the shop without paying, play the arcade machines with bought tokens, and the Roller Disco and Octopus Garden are also not part of the main site but are pay to use?
On the park site itself, there is a great deal more going on than just rides, there's other entertainment too. That's available to paid ticket (wristband) holders. Opening weekend it was Wall of Death, Punch & Judy, and many others. Keep looking at the website, there's a great deal happening. I assume all these have to be paid for by Sands Heritage, and therefore those buying wristbands have paid for this too.
Also, if cash had to be taken for individual rides that brings further delays, security issues, cash security problems etc, ride operators are better employed welcoming people onboard and ensuring safety.
For many, the Scenic may not be the attraction.
Forget Dreamland as it was, it's not like that. I think it's pretty good value for money, at less that £15 for adults, for a full day and as many rides as you can get on.
I gather TV ads have been appearing, which is good.