People should understand that when companies sign up the cricketers, its not for the love of the game or player, its pure economics. MRF is the 6th largest tyre manufacturer in the world with sales of close to $3 bn, majorly in India but also in UK/Australia/Lanka etc. It's a B2C brand, the more its in front of our eyes, the better recall value it will have. So when they sign up SRT or Lara or even some IPL player, it's because they know that a quality player will be batting approximately XYZ mins in an year and some ABC mn people (potential customers) will be watching him bat. So in their internal calculations, they assess whether a deal was good or not, based upon the money they had to spend per minute of viewing time of their logo. Of course the better quality of player will ensure better brand recall value. So though MRF may not be having sales in WI but when Lara would bat, a lot of people from Asia/Australia/Eng would watch him bat, all of whom are their potential customers. I might be getting too technical but broadly that's how professional companies like MRF or CEAT measures ROI on every dollar spend. Similarly for Britannia or CEAT, both of which are $1 bn+ sales company and like any other B2C company have to spend money on advertisement/marketing.
Anyway, point i want to drive is that how much money Babar make from bat sponsorship has very little to do with the quality of his batsmanship. A Shreyas Iyer with CEAT sponsorship might be making more money than Babar for his bat logo and that's because he plays IPL/international cricket and his bat is front of target audience (Indians primarily as i doubt any other countrymen would watch Iyer bat) 75+ days in an year. MRF or CEAT would not gain anything by making Babar a brand ambassador because CEAT/MRF doesn't have any sales (as far as i know) in Pakistan and Babar is not of the stature of Lara, that people would sit and watch him even when he's playing against some other country.
As far as Gray Nicolls is concerned, it does sales of approx. $25-$30 mn annually, and assuming it spends 5-10% of its sales on marketing, it's entire marketing budget won't be more than $2-3 mn. It has signed up more than 35 cricketers across England, Australia and Pakistan and even if top 20% would be getting 80% of sponsorship money, i doubt anyone would make more than $150-200K.