Sigh... bootstrap didn't get where it is by looking unprofessional.
I also don't understand wanting every admin interface one comes across to be a special snowflake, the opposite of what should be the case. We've known for at least 30 years (Apple HIG) that a standardized look and feel is a benefit to users, not a detriment. Not to mention dev maintainability.
I suppose billable hours decrease when reinventing the wheel is no longer necessary.