I would guess there is likely no increase in house price, especially for current solar panels. If I live in the house for the next 10+ years, it's questionable what value a 10-15 year old solar panel array will have, especially if the next owner will need to either change them out or remove them in 5-10 years
I'll argue that even in 15 years, you will not need to pay for labor to install and setup the system. Swapping out the old panels with newer, more efficient, and cheaper panels may be less than half compared to installing the entire system from scratch.