There have-ben and are plenty of religions, spiritualties and people in the world who regard meditation as a panacea - that is, a single cure for all ills, always good for everyone.
...Whatever ails you, whatever kind of personality; meditation will help if you do it right - and the more meditation you can manage (building up by steps), the better.
I think it likely that this idea arises from a particular metaphysical conception of deity and the world. Someone who regards deity as always the same - changeless; 'pantheistic', everywhere immanent, to be found in all things.
This is seen among self-identified Christians of an esoteric and mystical type; as well among Hindus, Buddhists, and New Agers.
As, for instance, the conception of Jesus in the famous saying from the ('Gnostic') Coptic Gospel of Thomas: Split wood, I am there. Lift up a rock, you will find me there.
If this is the case, and if only we could perceive it, we will never be closer to God than we are now - we are living in Heaven already...
Also from the Thomas Gospel: The kingdom of the father is spread out over the earth, and men do not see it.
But if we are already in God's presence because God is everywhere, and God is good; then why don't we know it: why aren't we always blissful?
Why do we perceive change, decay and death; if reality is unchanging perfection; and we are always immersed in that reality?
Something must be blocking our capacity to perceive this; and the answers given are usually twofold: we are blocked by the self-centered ego, and by the body.
Meditation is regarded as a panacea that is good for everybody and works for everybody; because from the above perspective all men suffer the same problem: all Men have an ego and a body.
Meditation is regarded a universal solution because it treats a universal problem. That is its theoretical and experiential basis.
When God is Not regarded as a personal being - there can be no personal relationship with God - and there is no need (or possibility) for any personally-specific solution to the problems of life.
In meditation - with sufficient effort, training and the right kind of personality - the 'ego' can be eliminated temporarily; and a vision achieved of how reality looks to one who has the assumptions of a changeless, timeless and all-pervadingly divine impersonal reality.
This is always 'a good thing' because it shows the meditator what he could have later, permanently.
Such meditators then often yearn for the time after physical death when they can discard the body - with its many distractions and localized vision - and can become pure spirit.
The great, and unfixable, flaw in such a perspective is to explain why an all pervading and good deity would create, or allow, a situation to arise in which ego and body was permitted to prevent understanding and delay the advent of a purely spiritual existence.
Especially when considering that egos and bodies are wholly dysfunctional - why bother inventing and implementing them in the first place?
There can be no satisfactory answer - nonetheless so strong is the desire, in some souls, for a bodiless life of changeless and wholly-receptive bliss, of passive (action-less) awareness of the all-pervading presence abstract divinity; an existence of peace, stillness, serenity...
Such that such rational, logical, commonsensical quibbles are set-aside in anticipation of the bliss to come, which - meanwhile - can be sampled by learning effective meditation.
This, I think, is how it comes about that so many people, for so long, have recommended meditation as a panacea.