Never store your wealth with third-parties is time-old crypto advice. Learn to use wallets.
Than where to trade if any exchange suddenly stopped all services and disable the withdraw. I didn't understand what is your advise and what you want to say there this not a solution and we can't make the growth process healthier. We need secure exchange but Bitgrail is dedicated to XRB that is nonprofessional what happened there.
I do understand your frustration but what @scumbust is saying may not be the complete solution for the current problem but it is a good advice though and it can really help avoid problems like this in the future, it's always best not to store a huge amount of money on an exchange and bitgrail as much as we don't want to accept it is a very shady exchange to begin with but because it's one of raiblock's fist exchanges and it was the exchange that works best before, we were blinded by it and avoided the warning signs that was all over the place. We do really need a secure exchange and lucky for us there's kucoin and binance that really has the security that we all deserve. I really hope that the devs will just freeze all the suspicious wallets that have been reported, in that way no stolen coins will be traded in any exchange. I think that will really help us move on from this and also as what you stated make the growth process much healthier.