Are Racket Modifications One-off or Perpetual Adjustments?

Several competitive players asked my opinion whether racket weights modifications should be one-off, or a series of perpetual adjustments.

Once, I replied a parent (of a tennis kid) by asking him how would he match the below 3 rackets to the 3 players below:

Racket 1: 100 sq inch, 360 grams strung, 27" long
Racket 2: 100 sq inch, 250 grams strung, 25" long
Racket 3: 110 sq inch, 300 grams strung, 28" long

Player A: 30 years old gym instructor
Player B: 7 years old school kid
Player C: 70 years old retiree

Even with zero information about their tennis skills or ability, the match up was completely predictable. No matter who I asked.

This is why I lean strongly towards a one-time adjustment. And this one-time modification should be able to tune the racket to at least a 80% match with the player's abilities.

We are not discussing beginners, or recreational players who have not honed their consistency. Although still useful, they would benefit more from coaching than racket mods.

Even if the seasoned player, or professional is still refining their strokes, I cannot see the constant need to re-tweak.

Racket weights like swingweight, balance, total weight, MOI, twistweight, recoil weight, etc, are far more correlated to the player's movements and strength, rather than skills.

Take the human body weight for example. Most people hover around a certain weight. Absent of special events like holidays or celebratory feasts, body weights usually maintain within a tight band of 2% to 3% over time. So much so, that doctors often use unexplained weight gain/loss as a clue for serious illnesses!

Similarly, muscle mass and strength do not vary much too. 

Even for gym rats who train relentlessly, they peak and plateau. And if they do not put in the consistent effort to maintain their diet and physique, they would drop back into their normal state of equilibrium. If their appetite maintains, they grow fat.

Hence the conventional wisdom is for the serious tennis player to use as heavy a racket as he or she can manage effectively.

This translates the game of tennis to one where opponents fight to out-power, out-run, out-last or out-wit each other. Whoever wields the "bigger gun" usually prevails, or have a significant advantage.

When the going get tough, or with new rackets being marketed aggressively, it is easy to fall into the lure of new equipment. 

However, every new setup, whether just weight tweaks or new racket, takes a long time to truly adjust and acclimatize. 

The player needs to test the racket on different court surfaces, different strokes, types of spin and pace, different brands of balls and narrow down string type and tension before putting it into match play. Easily a multi-months episode costing hundreds of dollars.

It is easy to tweak, but how much time, money and energy does a player have to go through a racket so thoroughly? Or risk losing an important match when the racket, or strings, "mis-behave" mid-match?

This is the reason why so many professional players would rather have a paintjob to endorse the lastest release instead of changing sticks.

If these top tier players in the world opt to maintain equilibrium, why should we be so quick to disrupt ours?