Are you saying Satan's kingdom is shrinking?
As Daniel said, the general trend is that it shall shrink. I am convinced that too many Western Christians take the current state of their country as what is happenning globally. If my eschatology was based upon the state of UK Christianity I would be very pessimistic indeed. Yet when we look globally we see thousands-upon-thousands of conversions in Africa, China and South America.
But of course our theology should be based upon Scripture, not our experience:
Psalms:
“All the ends of the earth shall remember and turn to the Lord, and all the families of the nations shall worship before you.” - Psalm 22.27
“O you who hears prayer, to you shall all flesh come…
By awesome deeds you answer us with righteousness,
O God of our salvation,
the hope of all the ends of the earth
and of the farthest seas.” - Psalm 65.2, 5
“All the nations you have made shall come
and worship before you O Lord,
and shall glorify your name.” - Psalm 86.9
“Nations will fear the name of the LORD,
and all the kings of the earth will fear your glory.” - Psalm 102.15
“All the kings of the earth shall give you thanks, O LORD,
for they have heard the words of your mouth,
and they shall sing of the ways of the LORD,
for great is the glory of the LORD.” - Psalm 138.4
“Let the peoples praise you , O God; let all the peoples praise you! Let the nations be glad and sing for joy.” Psalm 67.3-4
“May he [God's king] have dominion from sea to sea,
and from the River to the ends of the earth!
May desert tribes bow down before him
and his enemies lick the dust!
May the kings of Tarshish and of the coastlands
render him tribute;
may the kinds of Sheba and Seba bring gifts!
May all kings fall down before him,
all nations serve him.” -Psalm 72.8-11
Isaiah:
“It shall come to pass in the latter days
that the mountain of the house of the LORD
shall be established as the highest of the mountains,
and shall be lifted up above the hills;
and all the nations shall flow to it,
and many peoples shall come, and say:
Come, let us go up to the mountain of the LORD,
to the house of the God of Jacob,
that he may teach us his ways
and that we may walk in his paths.” - Isaiah 2.2-3
“For to us a child is born…
Of the increase of his government and of peace
there will be no end.” - Isaiah 9.6, 7
“The earth shall be full of the knowledge of the LORD as the waters cover the sea. In that day the root of Jesse, who shall stand as a signal for the peoples - of him shall the nations enquire.” - Isaiah 11.9-10
“I will make you as a light for the nations,
that my salvation may reach to the end of the earth.
Thus says the LORD, the Redeemer of Israel and his Holy One,
to one deeply despised, abhorred by the nation, the servant of rulers:
“Kings shall see and arise;
princes, and they shall prostrate themselves.”
“Kings shall be your foster fathers,
and their queens your nursing mothers.
With their faces to the ground, they shall bow down to you,
and lick the dust of your feet.”" - Isaiah 49.6-7, 23
Jeremiah:
“At that time Jerusalem shall be called the throne of the LORD, and all nations shall gather to it, to the presence of the LORD in Jerusalem, and they shall no more stubbornly follow their own evil heart.” - Jeremiah 3.17
Daniel:
“As you looked, a stone was cut out by no human hand, and it struck the image on its feet of iron and clay, and broke them in pieces… But the stone that struck the image became a mountain and filled the whole earth… The God of heaven will set up a kingdom that shall never be destroyed.” - Daniel 2.34, 35, 44
In Zechariah:
“Thus says the LORD of hosts: Peoples shall yet come, even the inhabitants of many cities. The inhabitants of one city shall go to another, saying, ‘Let us go at once to entreat the favour of the LORD and to seek the LORD of hosts; I myself am going.’ Many peoples and strong nations shall come to seek the LORD of hosts in Jerusalem and to entreat the favour of the LORD.” - Zechariah 8.20-22
In Malachi:
“For from the rising of the sun to its setting my name will be great among the nations, and in every place incense will be offered to my name, and a pure offering. For my name will be great among the nations, says the LORD of hosts.” - Malachi 1.11
Jesus gives us parables of the kingdom indicating that it will grow:
“‘The kingdom of heaven is like a grain of mustard seed that a man took and sowed in his field. It is the smallest of all seeds, but when it has grown it is larger than all the garden plants and becomes a tree, so that the birds of the air come and make nests in its branches.’ He told them another parable. ‘The kingdom of heaven is like leaven that a woman took and hid in three measures of flour, till it was all leavened.’” - Matthew 13.31-33