If anyone bothers to read my posts I have been rallying against the concept of diminishing returns.
Just today I posted about a $95 ethernet cable purchase (2 cables) hoping it makes a nice upgrade.
If the cables (when they arrive) make just a 1 percent improvement, in my system, that would be around a $1000 benefit. Other upgrades are free, like a cleaning tube sockets, or low cost tweaks like a new AC power outlet.
In a lesser system these upgrades might not be audible, but in a high end system the entire experience can be bettered by some inexpensive or modest upgrade.
While my thesis might be flawed in some ways, my point it that the benefits stack up and pays dividends.