I think the answer can be broken down very easily into few simple points. From my experience what I've seen is that US is one of the biggest consumer of paid software. So this makes perfect sense to incorporate there as a local address gives you some edge over business being run internationally. This might not sound very true but there is always some bias, but yes things will change in coming times very soon.
From a technical perspective if you see when you are building a SAAS product you will want to accept payment via subscriptions and Indian laws doesn't allow to do recurring charges. Services like Stripe and BrainTree don't work with an Indian entity or Indian bank account, so this can be a huge challenge.
Personally for myself the second was the major reason why I had to incorporate in US and not in India. Moreover Indian are looking into incorporation in Singapore now a days, it has some tax savings I think, but I'm not very through with it.
Incorporation in Singapore was costing me more when compared to US, because Stripe has a program called as Stripe Atlas, has helps anyone in the world incorporate in US with $500. If you would like to get an invite let me me know.
I hope that helped you.