You have to look like it like this, it is their job.
I know some small developer groups might be more flexible, but on a whole these people just do this for a living. (of course they made their hobby their job, so it's more fun than an average-joe job)
I have a busy job and people get on my nerves with demands and requests all the time. But my boss would never just give me a month off because I have given it a lot. It's a job, they do this everyday and mind their own schedule without too much notice of what goes on on the forum on a daily basis as far as I suspect. The really good ideas or pressing matters will reach them through the forum moderators and/or administrators anyway.
A month break means loss of money. Just doesn't work like that, it's not a thrid party addon making group that own their own time, these people work for a boss too, that wants certain things done by a certain date, and there is always more to do than there is time, in this business. (Well I don't know for a fact how VSTEP works, but generally speaking this is how it goes)
Giving them a month off is not something a forum population would decide for a sim developer, if you know what I mean.