Why are there so many awful Salesforce integrations?

I've been a Salesforce admin and developer for 3 years now, and I have had to deal with a handful of integrations now including Pardot, DocuSign, an accounting software that shall remain nameless, and a couple other things not worth mentioning.

To say there are some trade-offs to using some of these integrations is an understatement. There should be zero excuses for some of the recklessness and incompetence when it comes to these 3rd party add-ons.

I feel like Jesse Pinkman screaming "He can't keep getting away with this!!!" every time [management] decides to integrate with some 3rd party enterprise software that "integrates with Salesforce", only to find out it only does 20% of what we need and then the integration specialist tells us we need to create 6 new custom fields and 3 flows to gain some feature we thought would be native.

And never ask them why their engineers can't add the feature in their next update. You thought they actually have an engineering team? No they contracted with some offshore Salesforce dev shovelware company and they're just as clueless as you are on the inner workings of the integration!

“Integration” is really starting to become a dirty word for me now. Am I just hitting a bad streak? Or is this the norm? Why don’t we hold enterprise software to a higher standard?