Well it is certainly amazing to see an old business that was doing great (according to the owners) shutting down so abruptly.
But that's the decision you made, all it is left for us is to respect it.

I have one single request, if possible, although I'm pretty sure you have already thought of it.

Can you please make sure that for at least one year or two the domain name won't be dropped also, as I doubt the renewal fee would put a financial strain on you ?
By this we can make sure that the name won't be acquired by someone with the intent to profit (scam) based on your hard earned reputation.