The grass plays slower now claim and what would actually settle it

What court speed actually refers to

The phrase bundles together how much horizontal velocity a bounce preserves, how high the ball sits afterwards and how reliably the bounce is predictable. Those properties can move independently, so a surface can preserve pace while producing a higher bounce that gives a returner more time. A higher, more predictable bounce feels slower to a player even if the ball is arriving no later than it used to.

Because the experience is of time available rather than of velocity, player descriptions conflate several properties into a single word. Any investigation that starts from the word rather than the properties will therefore be chasing something that has no single referent.

Everything else that changed at the same time

Ball construction, string materials, frame stiffness and the physical preparation of players all shifted across the same period. Modern strings allow far more spin to be generated at high racket speed, and heavy topspin produces a higher bounce on any surface. A returner facing more topspin experiences more time and a higher contact point, which is exactly what a slower court would feel like.

Separating a change in the surface from a change in what is being hit at it requires holding one constant, which no one has done publicly. The confound is total, because the equipment and the technique moved together with whatever the groundstaff altered.

What could be measured and largely is not

Surface properties can be measured directly with standard equipment that records rebound behaviour and friction under controlled impacts. Those measurements would separate the surface question from the equipment question and would not depend on anyone recollection. Where such testing is done it tends to be internal, so the public argument continues to run on impressions rather than instruments.

The absence of published measurement is what allows the claim to be repeated indefinitely without ever being resolved. It is a genuinely answerable question that has been left in the category of things everybody knows.

Groundstaff decisions that plausibly matter

Grass species, cutting height, rolling regime and soil composition all affect how firm the surface is and how the ball interacts with it. Firmer soil generally produces a truer, higher bounce, which is precisely the property that reads as slower to a player expecting skid. Changing preparation to produce a more durable court that survives a fortnight of play would have that effect as a by-product.

That is a plausible causal path and it does not require anyone to have set out to slow the surface deliberately. Plausible is not demonstrated, and the distinction is the entire content of the disagreement.

Where the honest answer sits

The defensible position is that the playing experience has changed, that several candidate causes exist and that they have not been separated. Declaring that the courts were deliberately slowed asserts an intention as well as an effect, and neither has been established publicly. Declaring that nothing changed dismisses a consistent body of player experience that deserves better than dismissal.

Between those two lies a question that instruments could answer and that has been left to argument instead. That is a choice about what gets published rather than a limit on what could be known. A question that instruments can settle should not be spending decades as a matter of opinion between people who cannot check each other.