Both indicators (along with python) that this is an article written by a yet another data scientist that thinks engineering is unecessary. Data science is a field that is plagued by individuals having very specific narrow experiences that are often easy to engineer making them think they are experts in data engineering. Vertical scalability has a hard bound, if your algorithm changes complexity it could become literally impossible to move forward. Horizontal scalability gives you options, this is why we like it, not just because we like to overengineer systems, but because we don't like embracing hard limitations on the systems we engineer, especially when we often don't know yet what problem we are solving. Engineers often don't get the liberty of solving extremely specific instances of problems like data scientists do.