Does upgrading you system have to be on a logarithmic curve?

The law of diminishing returns for sure, not sure about the curve being hyperbolic or logarithmic? 

The last 10% is the most expensive 😀

the last 1% is very expensive.

It is not logarithmic, but rather linear, if you concur with the old-time experience.

For all us old-timers here, we remember the simplified anecdotal guideline casually referred to as the “Rule of Fourths”.

This was an inverse relationship that had its genesis in hi-end audio.

Simply put, once you chose to further upgrade while you now play in the high-end gear sandbox, upgrading further with a performance improvement expectation, generally required a four-fold dollar expenditure to get a 25% step-up in audio performance.

My take:

Because upgrading while striving for system synergy is a difficult and variable journey, throwing just money alone at it may parrot this homily and provide merit, …but … it still may not necessarily satisfy another parallel time-honoured adage:

“Price is what you pay. Value is what you get.”

- Warren Buffett

There is no great sound to be found for under $100k or so, speaking new suggested prices. So unless you can and want to do that just enjoy your system as it is. And I am talking one source system. However, if you must keep upgrading as most of us, including myself, double the cost, assuming that what you buy is not overpriced.