I don't think it's shameful, though just niaeve to expect it to work well.
To be fair I do think it is difficult to make a choice until you make an app of size you will not know about those edge cases.
My agency worked on a site which had ~1M+ pages and the backend became unusable (entries table was dead), task management had to be bespoke, search had to be dealt with by Elasticsearch amongst other things.
Can validate. Craft is amazing, by far my favorite CMS, but if you have a true enterprise site and need to do any changes to fields, it's a nightmare. Crashes the site constantly, only solution is to boost RAM.
As someone that has worked with Craft it has a ton of awful edge cases once you get deep into a project.
Craft absolutely does not scale.