Old is good - what our society needs is to keep contact with the past through the old; not to be 'relevant' and modern.
Religions too. All Christian denominations that have been strong and 'worked' seem to have maintained a link with the past via the old.
Old buildings - a church which meets in an old church building has a built-in advantage - since the setting intrinsically links the present with the past.
(That this advantage can be overcome is easily seen by the destructive, anti-traditional, past-rejecting Liberal Christianity which has emanated from the beautiful old buildings of Oxford and Cambridge universities. But still, old architecture has to be overcome - the Liberalizers will not really be happy until they can operate in a newly-built glass and concrete box without any visible reminders of the slave-trading, patriarchal, war-mongering, excluding bad-old-days.)
Robes and rituals are good, especially if they are old or backward-looking. Modernizers always want to introduce casual dress, causal manners, causal language, promiscuous chumminess with first names all around.
This is so as to be friendly, and welcoming, and not to exclude people, and not to be off-putting. But it is another break with the past, makes church the same as everywhere else, nothing special.
Every break with the past increases the influence of the present; and when the present is profoundly anti-Christian, every break with the past is an obstacle to Christianity.
In church, old music (and styles and instruments) tend to evoke a deep continuity with the past - modern music doesn't. It may have other virtues, but modern music is of the modern world.
This goes beyond enjoyability. It is about a mind-set that either recognizes continuity, or forgets it.
Old words - old language.
This is very important - perhaps the most important thing of all.
Things can be said in old language which cannot be said in modern language.
So when the Authorized Version of the Bible is discarded and an easy to understand modern translation is substituted, we find that the modern language simply does not allow Christians to say some of the things they need to say.
Because modern language has been created - in part - precisely to exclude the basis and also the substance of Christianity.
Tolkien knew this for a fact and knew it deeply - and he used archaic forms of language, he had to use archaic forms of language, as well as modern forms - in order to express things that were embedded in archaic worlds. The fact of the great and enduring success of his work shows that people responded.
It could be rejoined that a real Christian does not, should not, need old buildings, old formality and rituals, old music, old words; a real Christian only needs Jesus...
Well, yes, but...
To live the life of a Christian in an increasingly anti-Christian modern world, it is certainly very helpful to link-up with the past - in fact, without the links to the past, there aren't very many modern Christians to link-up with!
The context of Christian life and worship can help maintain alive and psychologically-active these links with Christians of the past.
This can strengthen and deepen and insulate modern Christianity, in a pervasively hostile environment.
If church is almost indistinguishable from the rest of the world - if church takes place in an aggressively modern building; with people wearing their normal clothes and shambling around in their usual daily manner; chatting casually using first names to friend, stranger and Pastor alike; singing recently-written songs accompanied by modern instruments; hearing Scriptures that are either in the style of modern bureaucratic memos or the style of pop music radio announcers - and hearing them expounded in the style of a jolly, jokey TV documentary ...
well, the least that can be said is that everything about such a church is working-against Christianity;
because Christianity is saying things for which modern culture has (deliberately) no place.
If, therefore, churches try to be completely modern, then they will find that they cannot expound Christianity.
At best, at most, fully modern churches can only tell-people-about Christianity - in hope they will at some time go and find it for themselves - but people will never experience Christianity in the church itself.
Such a wholly-modernized church operates rather as if they were telling-people-about the beauty of Shakespeare's poetry - but never actually quoting it.