Here's the church, here's the steeple: Where's all the people?

Sermon on the Mount   
1877 Painting by Carl Bloch

This question is often asked by those who see "church" and "people" as two different entities.  These are often the very same folks who track membership stats and empty pews.

A good place to start when addressing such concerns is the following question: What is the church?

Merriam-Webster lists a number of definitions, the first of which is this: "a building for public and especially Christian worship."  Next one down is not much broader in scope: "the clergy or officialdom of a religious body."  It isn't until the third definition that we get at the heart of the matter: "a body or organization of religious believers, such as the whole body of Christians."

The latter definition is more in keeping with the Greek word ekklesia.  This term was widely used by secular Greeks to indicate "a gathering of citizens called out from their homes into some public place."  In the Septuagint (Ancient Greek translation of the Hebrew Bible), ekklesia more specifically referred to the gathering of Israelites for either a specific purpose or as representatives of the nation.

The early Christian community then reframed this concept of ekklesia into "an assembly of Christians gathered for worship in a religious meeting," as well as "the whole body of Christians scattered throughout the earth," and even "the assembly of faithful Christians already dead and received into heaven."  Such definitions include individual and congregate believers who are located pretty much anywhere (on or beyond Planet Earth).

When "church" is synonymous with believers rather than buildings, the emphasis then shifts from capital to communal.  At that point, doors can open wide to receive additional Light.  

Resources

https://www.merriam-webster.com/dictionary/church

https://www.biblestudytools.com/lexicons/greek/nas/ekklesia.html