I have seven years between my two children, and haven't found it to be a problem at all. There are many ways to tackle it. In our case, for the most part the kids do totally separate things. But because home education is so much more efficient than large-group instruction, it isn't a case of me sitting with each child for six hours a day.
For example, last night my teen and I were up till an unearthly hour learning Spanish online together - we've just discovered the excellent free language teaching website Duolingo and have got a weeny bit obsessed with it. My younger one wanted to get in on the game but it isn't suitable for her because she can't read yet, so instead she will do the annual Junior Language Challenge when that starts up shortly.
Then this morning while the teen worked on her drawing upstairs, my younger dd and I were making a stuffed snake and she asked me to google some images of snakes. Then we had some questions about snake anatomy and behaviour and got quite sidetracked by reading about that, only returning to the project at hand after half an hour.
My ability to multitask is not great, but sometimes that works too. This evening dd1 was cooking the family dinner and kept calling out for advice on that, while dd2 was sewing the snake and kept asking me to tie knots etc. Neither was getting my full undivided attention, but neither needed it.
One thing we do always do together is going out to interesting places. Last month we went round the Houses of Parliament and all of us took away different things from it, but we all liked it. Sometimes we split up in these places if we want to look at different stuff, in which case I might bring along one or two of my older dd's friends so it will be more fun for her.
It's quite rare to find any destination which only appeals to one of the kids. I might take dd1 to a play next month for which her little sister wouldn't be able to sit still, in which case I will send the little one to be looked after by one of her friends' parents. We do a lot of kid-swapping around here.