Dahlias probably comprise about 1/3 of my growing space now, maybe a bit more. But if I only had dahlias I wouldn't have flowers until mid-July.
I have a pretty large front perennial bed with not a single dahlia. On the side of the house I have a very large bed that moves from shade to sun, and I have about 25 dahlias on the sunny end, with lilies and peonies right behind them, a couple of roses, lots of iris, moving to lady's mantle and columbine at the shady end, and some other stuff in there too.
In the back, a bed that is mostly shade, but the sunnier side is sunny enough for lilies and iris, with hellebores, ferns and hostas in the shade. One full shade bed that is mostly hosta, fern, bleeding heart and columbine. Another bed that has 20 dahlias in the sunny end, with lilies and peonies behind. And a largish vegetable garden with 10 raised beds (two (maybe three) of which I am going to put dahlias in this year, because I ran out of room) And two large dahlia beds with about 35 & 50 dahlias respectively.
All of my annuals and vegetables are grown from seed inside under lights.
So...........yes - time for more than just dahlias, but dahlias have been slowly taking over year by year. Better watch out - I used to only have 15 dahlias too