Define 'large' in this context?
Will thousands of protestants come clamoring at the doors of all the Orthodox Churches worldwide? I don't personally think so.
But in particularly welcoming parishes could not a reasonable amount of people find Orthodoxy and be received into the Church? I would say the answer is most assuredly yes.
At the Parish I am a Cate-quirer in, last year, there were 8 Baptisms and 1 reception by Chrismation. That does not count infants (there were more of those too!)
In the now -constantly- rolling Catechisis class there are another 5 who are not yet Orthodox. Will we all make it? God Willing, but just the demand to learn more, is there.
But I will say this only works when you have a parish that is friendly, welcomes people, stops to explain things, and so forth.
It doesn't work nearly as well if people are made to feel the wrong ethnicity, or that curiosity is a bad thing and to please go back away already!
I am very sure that my parish is not alone in the world, that there are many many others that see gentle-welcoming-guiding-being open ministries as a good and valid thing, and not just something that falls to Fathers and Matushkas.
So I throw down a challenge...next time someone visits your parish, make sure they have a copy of the liturgy booklet if your parish has them...show them where things are right then, and then you can let them follow along. After things are over, talk to them, make sure that they are introduced to people, if not the Priest or Matushka, a Deacon, a reader....-someone-. Get the coffee...encourage them, rather than discourage.
If you can't even help lead people to Christ and the Church when they walk though the front door and hand themselves over to you......