I doubt there will ever be a universal license. This is one of those ideas that sounds simple and great until you look at all the underlying challenges and realize it's that way for a reason
First and foremost, states like to have individual control over their own waters.There will almost always be differences in regulations, such as seasons, bag limits, minimum lengths, etc. Habitat, fish populations, and people populations are very different around the lake, which does not suit well to homogeneous regulations. It's hard enough managing the salmonid fishery cooperatively lakewide, if you toss a universal license in there, it will only add to difficulties.
Secondly, the way federal money is doled out by law includes numbers of licenses sold by states. Having a universal license complicates that somewhat.
Thirdly, different states have different budget needs. Taking away their flexibility to address those is going to be a non-starter.. The states also have different pricing for their licenses due to a large variety of factors. How do you price a universal license? You can't have individual states selling the same license for different prices. If you raise prices, you are going to price out a lot of people that only fish one state (which is the vast majority of folks), and that is completely unfair to them. If you sell a universal license for the price of one state's license, you're undercutting funding of all the other states, at a time when states are already struggling with adequate funding for natural resource departments. And if you raise the price for a universal license, then what's the difference from buying separate state licenses anyways, other than adding additional complications?
Finally, the number of anglers that fish multiple states is undoubtedly a very low percentage of the overall whole. This site is mostly diehard anglers that fish within 10-20 miles of 3 different states, so we're the exception rather than the rule. The existing system works well enough that it is not going to get disrupted for the sake of a small minority of people.
When you get down to it, if you are an Indiana resident, you pay 142 bucks for all 3 states. I dunno about you guys, but I spend more than that on lures and terminal tackle in a season. Even before gas, rods, ice, launch fees, etc. If you buy Michigan and Indiana and go fishing 20 times in a season, that's about 5 bucks a trip. Is it really that big of a hassle or financial burden to buy multiple licenses?