One of course knows an end will come, but ... coaching is an interesting profession in that it isn't all that demanding on time. It is certainly a very 'tough' profession, but it is not like an 8 - 5 punch the clock kind of job. There are periods of intense activity and a lot of travel, but even in season, there is a lot of free time, and freedom in terms of actual day to day schedule.
Geno has established a great team of assistants, administrators, and support staff, and he has learned the art of delegating authority - there was that wonderful half hour interview he taped in the middle of a game day practice - the assistants were hard at work and he was traveling down memory lane with Beth and Doris. He has spent the last eight years running three separate programs - Uconn, the US NT, and his food and beverage business, and he is dropping the NT, so it will feel like he is only working part time at this point.
He is at a place where his reputation as the best coach in the business and perhaps ever is well established, so there isn't the stress of building a reputation nor the false pressure to 'do more' to achieve success that can drive most people to work too many hours and push too hard. I think there is a level of relaxation you can catch in his interviews that is greater it used to be even a few years ago.
In terms of personal life - he probably would enjoy a few more weeks on the Jersey shore (and without the NT responsibilities he will get more time now), and the extended family is all in the northeast and the kids/grandkids seem to be doing well. I doubt they would move to another part of the country after retirement or even head back to the Philly area. I don't see him wanting to devote more time to his food business, and talk of a winery is just that I suspect - a pleasant alternative universe that it is fun to think about, but not real. And I think he recognizes retirement for what it really is - a chance to get away from a job that takes too much time and isn't fun. He loves his job 90+% of the time and is he really going to find something to better fill his hours between good food and better bottles of wine.
And it has been a long time since he recruited someone he wasn't going to like coaching - he really likes his players and recruits. They may frustrate him (I am sure they do) but that just adds to the fun of solving the problems that develop. He likely will never experience a string of four NCs in a row again, but that was never the most important thing for him anyway.
So ... I do know the end will come sometime, but I also wouldn't be surprised (health reasons excluded) if he found it very hard to walk away, and continued to coach well into the next decade.
(I see this with college professors, too - many continue to find real pleasure in teaching into their 70s, and those that retire early, often continue to do all the fun things associated with their job, just dropping the freshman intro course teaching. They keep writing, take on a few PhD candidates as advisors, give talks as professional conferences, etc.)