Was it actually rebuild from scratch? Rebuilding and taking over maintenance and support are two different efforts.
Why it had to be rebuilt? Was there a really unsuccessful attempt of a handover? Why was it so hard to hand over? Are we certain that documentation and training was sufficient for it to succeed?
Was ongoing support taken into account? Maintenance, new features, patching, monitoring - was it hard, was it clear for others how to approach those topics? Was the architecture easy to follow and pick up by others?
Expecting that others will be as genius as you may be seen as positive aim at perfection. It may also be seen as bad teamwork that will build up costs later on. Companies create standards, use "approved" frameworks and copy-paste solutions because it's then easier to support and require less people with less skill. It's hard to recruit already, you don't have to over-complicate solutions and make it even harder. Then there is a day in which your product dies on production and there is just one person who can figure out what is going on. For me it's a clear sign of poor management and we should all stay away from such practices.