Comment by branko_d

Often, this is presented as a tradeoff between the cost of development and the cost of hardware. However, there is a third leg of that stool: the cost of end-user experience.

When you have a system which is sluggish to use because your skimped on development, it is often the case that you cannot make it much faster no matter how expensive is the hardware you throw at it. Either there is a single-threaded critical path, so you hit the limit of what one CPU can do (and adding more does not help), or you hit the laws of physics, such as with network latency which is ultimately bound by the speed of light.

And even when the situation could be improved by throwing more hardware at it, this is often done only to the extent to make the user experience "acceptable", but not "great".

In either case, the user experience suffers and each individual user is less productive. And since there are (usually) orders of magnitude more users than developers, the total damage done can be much greater than the increased cost of performance-focused development. But the cost of development is "concentrated" while the cost of user experience is "distributed", so it's more difficult to measure or incentivize for.

The cost of poor user experience is a real cost, is larger than most people seem to think and is non-linear. This was observed in the experiments done by IBM, Google, Amazon and others decades ago. For example, take a look at:

The Economic Value of Rapid Response Time https://jlelliotton.blogspot.com/p/the-economic-value-of-rap...

He and Richard P. Kelisky, Director of Computing Systems for IBM's Research Division, wrote about their observations in 1979, "...each second of system response degradation leads to a similar degradation added to the user's time for the following [command]. This phenomenon seems to be related to an individual's attention span. The traditional model of a person thinking after each system response appears to be inaccurate. Instead, people seem to have a sequence of actions in mind, contained in a short-term mental memory buffer. Increases in SRT [system response time] seem to disrupt the thought processes, and this may result in having to rethink the sequence of actions to be continued."