You know it's an extension not an upgrade right?
You get 3 months for $50 then another 12 months for $60.
Or you get your first 12 for $75 then your next 12 for $60
You don't lose time. Your first 3 were just more expensive because you chose for them to be that way.
It's not that the 3 months is over priced, it's that the 12 months is under priced to provide incentive to enroll for a full year and not just 3 months.
It's not punitive, it's an incentive and reward for electing to pay for a year instead of 3 months.
This is actually the third time in a thread that people have referred to 'incentives' as if they were the norm, and that they had been somehow punished by not receiving them. (the other two being with pro membership) $50 is the norm. The rest is a bonus. Not the $75 being the norm, and the $50 is a punishment!
However, would an 'upgrade' option be appealing? Where at the end of 3 months you can pay say $30 instead of 60 and you get 9 months extension to bring you in line with those who paid for 1 year up front. (plus $15 to keep the 1 year incentive)
Any other model would then punish people who paid for a year in advance, and reward people for exploiting the system and buying 3 months so they got a cheap '1 year' upgrade.
The real question for me, if I was to put myself in Andy's shoes, is how to broaden the appeal of the club. One issue is that you have people (like me) who are essentially interested in one theme, for one site. Once that theme is chosen all of the ones from months past are of zero value and all of the ones in the future are only of interest to the degree that new features can be retrofitted into the chosen theme. So the practical value of future themes is low.
In which case, as you said yourself, it's the same price as buying a one off template. Except:
- You get much better support
- You have the option to change your mind (even if you don't exercise that option it's there which a one off purchase doesn't give)
- Until you decide on a template, you can change and test as many as you like
- You get 3 more templates to choose from which are almost always better than the existing ones
Where is the lack of incentive or appeal? I mean seriously. A club is 10000000* better than a one off purchase for the same price. The only thing missing is free beer and a foot massage (and even then Dave Gee will give you that if you join the Pros.. apparently... Though I am still waiting for mine ;D )
The long term value is not really there for someone who has a static site, and doesn't want to ever upgrade their template you are right. But that certainly isn't a good enough reason to open to forums up and sink the company. 
A template club isn't supposed to give long term benefits to those customers. Not everyone needs to buy a prepaid monthly train ticket either. It doesn't mean that the appeal of monthly prepaid tickets needs tweaking.
It doesn't make those customers bad, or the template club bad. It just means they aren't matched for a long term relationship.
One idea of what RT could do (and maybe is doing, though they seem to be doing it tied to each new template) is to offer custom modules only to subscribers--a version of their login module would be high on my list. That would be something of value to single-template users.
At which point RT would get a stream of complaints about how they have been 'tricked' into buying a template which doesn't come with the necessary modules that they need. Or that they don't have access to them.
It's a lot harder to justify why someone can't have access to a static information product as opposed to a service which requires manpower.
Perhaps RT could offer 2 hours of time helping troubleshoot/customize people's sites per year. Whatever--RT should be thinking more carefully about the single template uses (like me!).
Ouch, can you imagine the workload for even just a couple of hundred members? And what do they do when the 2 hours is up? Just walkaway with the job half done or finish the job even if it takes ten hours? but then everyone will want ten hours because one person it. or if they walk away halfway through people will be even more unhappy than if they never started! Sorry, but I can't see this working. :-[
I know it was just an off the cuff idea though. 
Does RT need to try to provide incentive for these people? They don't really contribute to the community because they don't have enough interest in other sites/templates/modules. Adding incentives for these people will make it harder to attract the people who do want to contribute to the community.
Scary as it is to say. Not everyone needs, or should need to be a lifetime RT member. Some people will need to come, and then go. They are happy, RT is happy, everyone is happy.
Wimbleton hasn't put goals at the end of the tennis courts, and made the players kick the ball around, because they are there to serve tennis fans, not soccer fans.
RT is here to serve longterm site builders with multiple sites, or who want to have variable templates.
It's only when people want more than what they paid for that they get unhappy. It isn't RT's fault they didn't take the time to read the very clear club agreement. Either way, they still get better value for their money than any other club or template purchasing method.