The key to succeeding in a DBA is to stay motivated. Being a good scientist is secondary.
As you have seen, a DBA is filled with loneliness, challenges, uncertainty, hard work and delayed gratification. You will be tempted to quit many times, so if you want to successfully complete your DBA programme, you have to stay motivated.
Each student has his/her own reason for doing a DBA, and each reason is equally valid and important. Ideally, you should start your research work for a DBA with a personally satisfying reason to make sure the satisfaction level of your motivation won’t go down. If you’re using a doctoral degree to help you land a career you’ve always dreamed of, focus on progress, as the ultimate achievement will eventually come.
Ask yourself “Am I closer to my goal than yesterday?” rather than “Did I meet my goal?”. A DBA is a roller-coaster, full of ups and downs. Yes, there are plenty of ups, and most of the times they compensate for the downs.