The suburban churches where I live are always full. However, the churches in the downtown area of the city where I grew up are having trouble with attendance because the parishes where they are located don’t have many people living there anymore. Some churches have closed or merged with other parish churches. I believe it has a lot to do with the location of the churches.
In most cities, “downtown,” or as we call it in Charlotte, “uptown,” is not where a lot of people live. Uptown Catholic churches in Charlotte have good congregations if they are heavily into traditional liturgy and devotions, not because there’s a local congregation on the ground. This is Billy Graham country - we don’t have a lot of center-city Catholic Churches from the old days, like they do Up North.
We have big congregrations in all our churches in the Charlotte area, though. My parish is over 1/4 Spanish-speaking, but we’re also SRO at the English Masses. Parishes in the main residential areas of Charlotte, especially those with notably orthodox priests and liturgies leaning traditional, are also packed. We have a Vietnamese parish, a Filipino-majority parish, and more than one that are majority Spanish-speaking. Our problem is expanding the facilities (past the zoning boards and the EPA ... my parish is having to move because of an endangered freshwater clam!!!).