I think this kind of thing will only ever appear on new TVs and boxes, so there will be a need to purchase some extra equipment. There is no incentive for manufacturers to continue to release/allow new updates and firmware for their devices once they are a year or so old. They will have moved on to their latest devices.
Not really, quite a few manufacturers have their equivalent of an 'app store', where you download or update various services and applications and install them on the equipment. Panasonic, Samsung and Humax being 3 brands that do this.
However there are certain restrictions with such services. My TV has iPlayer on it, but as Brekkie says, it apparently won't get an ITV Player or 4OD app because they are currently exclusive to Samsung tellies. I assume this new product will be platform neutral like iPlayer