Startups absolutely have time to market and cost of developer time. Using a language that can get you there in 1 month instead of 1 year is very important and has nothing to do with the cost of technology.
There's very little to no correlation between "difficulty to get adoption/sales" and "time to market". This very article is about displacing Amazon (founded in 1994) in the ecommerce space and the very top comment is about OpenBazaar (started in 2016). You can develop your business in golang or rust or f#, but if the business idea is irrelevant or unviable then your developer economic productivity is exactly zero.
I don't think either language I mentioned there could offer you 12 productivity against the rest. Yeah, people have preference, for sure, but if you can build something in a month time using Node, someone else could probably clone it with Python/PHP in a month time as well.
Whether you can sell your startups or not, is a completely different matter