I think the lesson here is that with great product market fit everything is under engineered, with poor product market fit everything is over engineered. Statistically you are more likely to be building an over engineered product with poor product market fit than you are to be building an under engineered product with great market fit.

Now is over or under engineering a bad thing? that depends on how many resources the company can muster, your customer tolerance to bugs/failures, and whether you can build a small subset of features well. In practice I've observed products with fewer, but well built features tend to succeed more so than buggy featureful products. Large companies may opt to overbuild everything simply so that they can prove that the product was bad rather than having to decide whether it was product or execution that failed.