I was a 3 time buyer at a Chevy dealer. I bought used from them.
Sorry, the dealer was not my reason. It was the sales person.
I clicked with the guy. I liked his sales technique and he was more than willing to run all the slow process work in his free time while I was at home watching Netflix or working. I didn't have to sit for hours dealing with the normal drag.
I may be a special case ...
There is another dealership that I did check over and over again and that was because the Toyota shop was efficient, had cafe lattes on tap, great chairs to sit in and over all not a bad place to hang out while waiting.
Today ... not sure what I'll do since I moved. However, I will definitely consider driving 3 hours to visit my sales guy who has moved on to another store.
Is it your sales person the reason or the dealership? Is it just brand loyalty?
I would say a deeper look at why repeat buyers are happening or not. This would be beneficial to your overall sales strategy.