I am a Catholic. so that's all I'm onvered with.
Do you mean to say "covered with," here? Oh well, no matter. What I would say to this is that I am catholic too... part of Christ's one holy, apostolic, catholic ~
universal ~ Church. And as of right now, that Church is invisible, meaning that we don't know for sure who all is actually a Member at present or will be at some point in the future. We can know for ourselves, because we know God is working in us, and we can have opinions regarding others based on the outward evidence ~ their works, their fruit, (or lack thereof) of the faith they say they have.
...the number of PROTESTANT pew-fillers is rapidly-declining as well. This problem plagues ALL of Christianity...
Ah... "plagues"... well more on that in a moment. But yes, pew-fillers, church-goers... sure, there is a shakedown occurring, which I think is what you're saying here. There has always been a discrepancy between the number of those professing to be Christians and those to whom God has actually given true faith ~ His assurance and conviction ~ those for whom He has
"taken out the heart of stone and given a heart of flesh." God, through the prophet Ezekiel says this very thing:
"I will sprinkle clean water on you, and you shall be clean from all your uncleannesses, and from all your idols I will cleanse you. And I will give you a new heart, and a new spirit I will put within you. And I will remove the heart of stone from your flesh and give you a heart of flesh. And I will put my Spirit within you, and cause you to walk in My statutes and be careful to obey My rules." (Ezekiel 36:25-27)
God alone sees ~ and changes, regarding His elect ~ the heart. He works salvation in us. This is how He builds His kingdom, His Church, which is not a building or an institution or a particular organization, it is a people, His people. He calls this people unto Himself, regardless of anything else other than His sovereignty and His glory. And He will, in the fullness of time, bring it to completion. As Paul says:
"So then (we) are no longer strangers and aliens, but (we) are fellow citizens with the saints and members of the household of God, built on the foundation of the apostles and prophets, Christ Jesus Himself being the cornerstone, in Whom the whole structure, being joined together, grows into a holy temple in the Lord. In him (we) also are being built together into a dwelling place for God by the Spirit." (Ephesians 2:19-22).
God is doing this. God was doing this then, when Paul wrote that, 2000+ years ago, and He is doing it now! And So, the number of believers has always been increasing; God has been, is, and is continuing to build His kingdom. And one day ~ maybe one day very soon, even in our own terms ~ the fullness of the Gentiles will have been brought in and the partial hardening that is upon Israel removed, and in this way all of God's Israel will be saved (Romans 11:25-26).
As for "plaguing Christianity," it can be concerning or even distressing, seeming that there is no longer any growth, but that's not true; as I said, God is bringing Israel to its full number... He has not stopped or quit, or "given up." :) I would actually call this "plague" a good thing; God is making His Church more and more visible, and more and more pure.
– from Christ’s Catholic Church all the way down to your man-made “denominations” . . .
I'm sure there will be disagreement here, but the Catholic Church ~ like the Protestant "Church of Christ," among other examples ~ is a denomination. That's really not a disparagement, or a ridicule, or a denigration of Catholics ~ or members of the Protestant "Church of Christ" ~ in any way, although, certainly there will be many, and you may be one, who bristle at or take umbrage to that. Hey, there are many who don't want to be associated with any particular denomination, so they call themselves non-denominational Christians, but the irony in that is that they have created the Non-Denominational denomination... :) ...of which there are many variations, so there are actually many non-denominational denominations, which is ironic indeed. :)
But you know... here again, I would actually call it a good thing in a way, because we are striving for ~ we all want this great unity Paul is speaking of in Ephesians 4:1-16. But, because of sin, we may disagree concerning things, even Biblical things. Most should not be cause to break fellowship, but some are, obviously, so we congregate with folks who we agree with and strive for unity as much as possible... and long for the day when there will be no more sin or disagreement. It's going to happen... :)
And pulling back in what I just said, God is building His kingdom, and his construction is not confined to any one denomination. :) Included are people from every tongue, tribe, and nation, and will be as the grains of sand on the seashore, as the stars in the heavens... an innumerable multitude.
But for now... :) For now, I would implore, beseech, and encourage us all to not perpetuate and stir up any more dissention or disagreement or contention than there already is. :)
Grace and peace to all!