It is indeed my opinion too. In non-standard workflows, handcrafted code/application will most likely beat generic frameworks(not true for some cases). I have conflicting thoughts about this. Nowadays industries are very fast-moving, they generally can't afford to do it all for each of their use cases. So they tend to pick up generic frameworks. But I have seen many managers picking the wrong tools for the job and vastly overestimate their future needs. Everyone thinks that they are going to process petabytes of data, and they make the decision to use these generic distributed frameworks from the beginning to avoid the future scale. It rarely happens. Most of the time, they end up spending money on Cloud because making something distributed comes with a lot of redundancy to provide fault tolerance and yet not as performant as single machine performance due for data up to few TBs. Even here, if you take that parquet example, my hand-coded Rust code beats the Rust RDD version by 4x. I guess we can't change this attitude. So it is better to aim for improving these libraries.