Having knowledge of technology is not enough to become a BA. Several developers changed their career to become BAs because they thought that they know technology and coding and they can attend client meetings and gather requirements. However, they have severly failed because of lack of knowledge on business side. I can give you some examples: Imagine sitting with VP of Sales and he is talking about his requirements such as: 'we need some sort of reporting to give us insights on sales trends and projections.' Now if you don't know what's sales trends and what is projection and what this kind of reports need, you can't ask further questions or you can't even note down this 'requirement' because it means nothing. If you know sales, or have ever been a sales manager, you will ask: right, we can provide any report of your choice, do you need these reports based on regions/zones/countries or do you need it based on SKU/product line/proudct category wise? Also, for the projections, do you have any particular formula in mind, or we take simple trend projection based on past week/month etc. to calculate projections? 

Or imagine you are sitting with finance manager of a bank and interviewing him to find out his requirements for loans management software. He says: we must have flexibility to choose floating rates by it's name or define a fixed % as base rate. However, we would add some margin to this base rate, and the amortization of the loan must be calculated based on base rate + martin. But if the applicable rate drops down below floor rate we would take floor rate. Now tell me, how would a developer respond to this?

That's the reason the BAs must have strong understanding of business to succeed in this role. 

It's true that some developers understand business because they worked for long on one system. However, there are also developers who work for nearly a decade on a system and yet don't understand the business behind the system. So, I agree that there's a bright side, but the catch is that the developer must learn the business side to succeed. Just like business managers need to understand lots of technologies to be a successful BA.