Anglo-Indian families did not historically need a matchmaker. An aunt knew a family in another town, a priest knew two families in his parish, somebody's colleague had a niece. The introductions happened because the network was dense and everyone was inside it.
That network had specific requirements, and it quietly lost all of them.
What it depended on
Density. Enough families close enough together that any two were connected by a short chain.
Shared institutions. The school, the parish, the railway establishment, the club — places where families met without arranging to.
People who kept track. Usually older women, who knew which families had children of marriageable age and considered it their business to connect them.
Everybody staying put. The network only works if the people in it are reachable.
What happened to each
Density went with emigration and with the decline of the colonies. Families that were four streets apart are now four countries apart.
The shared institutions thinned. The schools remain, the parishes are mixed, the clubs have aged.
The people who kept track are largely gone, and nobody took over. It was never a formal role and so it was never handed on.
And nobody stays put. A community where a third of each generation emigrates cannot sustain a network built on proximity.
What this leaves
A community whose members are still perfectly willing to marry each other, and no mechanism for them to find out that the other exists.
That is a very specific problem. It is not a shortage of people, and it is not reluctance. It is an information problem — in Perth there is somebody looking, in Bangalore there is somebody looking, and neither has any way to learn of the other.
What replaces it
Something that does deliberately what the aunts used to do incidentally: keep track of who is looking, know enough about each family to judge a fit, and make the introduction.
The difference is that it now has to work across countries rather than across a parish, and it has to be done on purpose rather than as a by-product of everyone living in the same three streets.
The old system was not better at matchmaking. It was simply running all the time, for free, because everyone was in the same place. Once that stopped being true, somebody had to do it on purpose.