Plus in 5 years the company might not have the same sales and marketing teams, management or even owners.
I'm struggling imagining who can afford the equipment to run 'the latest tech' but will not be able to afford a game that uses it. I strongly suspect 'the latest tech' is important mostly to the privileged markets.
You might be right about the marketing. A hit game will probably be just as profitable later; maintaining or growing its own hype. The bigger problem I think is for games that are flops. Companies probably want to sell as many copies as possible before word gets out; and greatly staggering releases will result in a lot fewer copies being sold as you suggest.
Tech just doesn't make the gains it used to any more.
Back in the 90's a 4 year old machine would be lucky to even start a new released game, let alone run it at close to max settings.