They would get the same money and more from several deals instead of just one, and hopefully use the money in a good way. The same goes with the Porsche licence - just doesnt make sense.
Well, it actually does make sense from the perspective of the license holders. Why? Because with the "exclusive" licenses they are obviously getting bigger profits. How do I know that? I don't, but it is a heavy capitalism and if the reality was different, I am sure they would pursue the path where they can reach bigger profits (or any other side-benefit).
I will use the example of the F1 license rights before and post 2003.
Before 2003, the FOA was very liberal regarding F1 licenses and (almost) any studio (publisher) that wanted an F1 game could come to Ecclestone, place the offer and get the license. It was Sony who made a precedent in 2002, with securing exclusive rights for the F1 games in the period from 2003 to 2007. Noone except Sony was able to use any content related to licenses covered by FOA.
Due to increased license-fees announced by FOA in 2007, Sony opted out of the agreement and left to license to the other bidders. When heard about the F1 license being freed, Activision bought Bizarre Studios in intention to have them develop multiplatform F1 title. However, they were not willing out to pay alleged 15 million $ annually to FOM in order to get the rights. They were using the fact they have one of the best F1 development studios in the line to develop the game (it was former Bizzare - under the Psygnosis name - that developed legendary F1 and F1 '97) as the leverage to get lower cost. However, they didn't count on Codemasters willingness' to shell out 15M$ to Bernie. Deal was sealed in 2008 and Codies got the license, and in a sad turn of events, Activison dismantled Bizzare afterwards.
My point - if the multi-license could get Ecclestone more money, he would opt for it. But here are the actual stakes: with EXCLUSIVE license, he is SURE about annual income of 15M$ during the contract. He does not have to worry about market-caps, focus trends and similar things that get in the way when you have free license and you leave to the market to determine does it want to pay for your license or not. When you have "floating" license, your income depends on willingness' of each potential buyer to actually purchase a license for every year.
I presume it is exactly the same situation for the Simraceway. At some point, when those hedge-funds were investing into the Simraceway, someone thought how paying a hefty sum of money to McLaren for complete exclusivity of their portfolio will be a good marketing investment. McLaren saw a business opportunity to get that hefty sum as 100% certain income. And the agreement was settled. Easy-peasy and 100% logical.
Regarding Porsche, it is a more complicated situation. No-one know anything with 100% accuracy, but it seems how both companies (EA and Porsche) have their interest covered. With regular paying for the Porsche license, EA is securing own leverage on the market for their games and they use it to highlight that particular content as comparative (contentual) advantage of their titles. In the same time, Porsche is 100% certain about their annual income based on the license agreement and they do not have to worry about potential loss of such income if the license is made "floating" and their income become dependable of the number of the potential users by year.
It is really simple IMO. Yes, it does benefit to actual players, but it probably absolutely benefits to all other involved parties (to at least some margin).