You don't understand.
ReplayTV is the perfect appliance. And plenty of people want it to remain that way. WiRNS takes all the appliance out of it. Plenty of people will be happy to leave their systems in place and go ahead and pay the $7/month to keep their appliance going.
Your "little bit of work" may be little to you, but the convenience of not having to fiddle with things they don't understand is well worth the few bucks to many people.
And there's no reason for those who provide the service not to charge for the value they're providing.
The "group of enthusiasts" you refer to are NOT the market for the few bucks/month. They'll fiddle and twiddle and talk the ins and outs of WiRNS all day long for the rest of their lives, but in the meantime plenty of people are happy to sit down and continue to watch ReplayTV--and will happily pay for the privilege.
Nothing in life is free...either you gain the knowledge and fiddle and twiddle and be your own tech support (like I am with 7MC), or you pay someone to take care of it for you (like many do with Tivo, cableco boxes, etc).