D. Krindatch, national coordinator of the U.S. Census of Orthodox Christian Churches, said the practicing Eastern Orthodox population in the U.S. was 675,000 in 2020, down from 816,000 a decade earlier, and most parishes lost members after the outbreak of the pandemic.
Which Orthodox churches? Any data which includes the Greek Orthodox Archdiocese will be skewed. If you look at the Oriental Orthodox only, you will see an increase over 2010 due to the high birthrate and immigration. The same is true of the Assyrian Church of the East. Neither of these groups would be counted by an Eastern Orthodox survey, whereas the Greek Orthodox Archdiocese, which is contracting for reasons I explained, as well as related denominations such as the American Carpatho-Rusyn Archdiocese, which suffers in my opinion from having a Greek bishop rather than a Carpatho-Rusyn bishop (ethnocentrism is one of the major problems with the Patriarchate of Constantinople, particularly the Greek Orthodox Archdiocese, much more so than in the UK, where Metropolitan Kallistos Ware persuaded many British people to join and was himself English). Furthermore, such a survey would not count the members of the Old Calendarist churches, which have received many disaffected Greek Orthodox Christians from the Ecumenical Patriarchate, but are not regarded as canonical.
Furthermore, the pandemic hit everyone equally, so your inclusion of that is further distorting the statistics. Also, in the Orthodox Church most parishioners are not members. Members are limited to those who donate to the parish and vote in elections for parish offices. You can be a member of the Orthodox Church and a parishioner at a specific parish without being a member of the parish. Indeed at most Orthodox parishes, the paying members are a minority of the total parishioners, and it is actually a sign of bad health if most or all of the attendees are also members (conversely, it is also bad if very few are members). And I would expect parish membership to be down, since the economy has been plunged into chaos and people don’t have the money to donate that they had before the pandemic. But to summarize: in Orthodoxy, membership in a parish implies a specific financial commitment to the running of the parish; it does not equate to being a parishioner, whereas in many Protestant churches, anyone who joins a parish is counted a member of that parish.
As far as Google saying that the Catholics and Protestants are growing faster, that’s pure nonsense. I doubt Google itself said that, but rather you clicked on a polemic link that said that. It is well known that the mainline Protestant and the Roman Catholic Church have lost members at a time when most Orthodox Churches have gained members. The only Christians who for the time are growing faster than the Orthodox are the Pentecostals, and it is expected that the main clash in the future will be between the Orthodox and other liturgical churches and the Pentecostals.
But let us say for a moment that the Catholics and traditional Protestants were growing faster than the Orthodox, which they aren’t, but if we pretend that’s true, my point still stands, in that from the perspective of the Catholics and the largest Protestant denominations, namely the Anglicans, Lutherans and Reformed (in that order), the preferential status of house churches is problematic in that it represents the spreading of potential heresy. There is an immediate need for missionaries who will provide the house churches in China with theological guidance and ensure that they follow the doctrines of traditional Christianity, as exemplified by the Eastern and Oriental Orthodox, Assyrians, Catholics, Anglicans, Lutherans, Methodists, Presbyterians, Moravians and related denominations.
Also it disturbs me that you continue to ignore the horror of the genocide perpetrated against the Orthodox Christians in China, who represented one of the largest denominations, but were wiped out because Mao became suspicious of them after he fell out with the Soviet Union (nevermind the fact that the Chinese Orthodox Church is not a part of the Moscow Patriarchate but the Russian Orthodox Church Outside Russia, which was fiercely anti-communist; that is perhaps the real reason the Orthodox got purged). In Harbin there is a beautiful Orthodox church which survives as a museum. It is my prayer that the Divine Liturgy once more is celebrated therein.
Meanwhile, in Hong Kong, Macau and Taiwan, the Chinese Orthodox Church is thriving, and it is also doing well in Korea and Japan, where, as stated previously, the main competition tends to be Pentecostals and other Charismatics.
In addition, in Brazil, which has a substantial Chinese expatriate community, the Polish Orthodox Church has been growing rapidly; whereas the Russians, Syrians and Greeks accounted for the majority of Eastern Orthodox growth in the US, and the Copts, Assyrians and Armenians for the Oriental Orthodox growth, in Brazil, it is the Polish Orthodox Church which is doing most of the evangelization (due to a historical oddity, the Portuguese Orthodox Church, which has since broken away from communion with the Polish church and become non-canonical, however, the Brazilian parishes remained a part of the Polish church.