The foolish virgins are those who profess to be christians, but they haven't actually been born of the Spirit. Outwardly they look the part, but there's been no inner change. In every church congregation you have a mix of believers and non believers, some of which will leave it too late to be saved, and the door to the Ark will at some point close. (Yes, the world is made up of both wheat and tares, but this particular scripture is addressing the tares within the church congregation)
For me, V11-12 confirms this fact: "Afterward the other (*foolish*) virgins came also, saying, ‘Lord, Lord, open to us!’ But He answered and said, ‘Assuredly, I say to you, I do not know you.’
It says He does not know them, so they were never His. Notice He emphasizes the fact they call Him Lord... something that those in the christian world do, but He was never truly their Lord.
And then compare this scripture to this lost group mentioned here on judgment day, who professed to be christians but were never saved, and here they are trusting in their works...
Matthew 7:21-23: "Not everyone who says to Me, ‘Lord, Lord,’ shall enter the kingdom of heaven, but he who does the will of My Father in heaven. Many will say to Me in that day, ‘Lord, Lord, have we not prophesied in Your name, cast out demons in Your name, and done many wonders in Your name?’ And then I will declare to them, ‘I never knew you; depart from Me, you who practice lawlessness!"