There are certain situations to consider. I am in contact with 2 people in Fiji who have limited ability to assemble with others. But if we can assemble with others we should.

"Not forsaking the assembling of ourselves together..." is an admonition from Hebrews 10:25. Christian fellowship is a pleasure that one should look forward to. Examples in the book of Acts show that Christian behavior would include assembling with other Christians. Instead of considering assembling with others as a litmus test of faithfulness, one might consider it as a contributing factor for faithfulness in other areas: love, obedience, kindness, perseverance, patience, etc.

Many times a problem that appears is in thinking of the church in materialistic terms. For example, many think of the church as a building or a corporation. There is nothing wrong with using a building and there's nothing wrong with incorporating so long as we keep in mind what the church is.

Where is the church?

Where is the temple?

If you have the Spirit of God dwelling in you, then you ARE the temple (1 Corinthians 3:15). You and the Spirit filled Christians you assemble with are the lively stones of the temple (1 Peter 2:5). And the stone that was disallowed by the builders has become the head of the corner (1 Peter 2:7). Christ is our Chief Corner Stone. The more we can be like our Savior, the more we reflect faithfulness, assembling with others being only one attribute out of many.