What merits are you describing? MD schools make huge impacts in not just research but in community service, public health, ethics, education, etc etc. DO schools make similar contributions as well.
Its not the letters, its being able to have as many opportunities as you can that as a DO you dont have. If you want to be a med educator you can go to an MD school and follow a MedEd track. Not a single a DO school offers this (though you can be an OMM educator if you want...). If you want to focus on research, an MD school has a track for you that includes journal clubs and mentorship. A journal club at a DO school? Nothin.
If you want to do academic medicine you just made it 10x harder to do so and guess what, youll end up a community doc who's unhappy because even though your step score was great, you were never accepted to a university residency and you know why. Sure, youre a practicing doctor but it wasnt the type of doc you wanted to be. Simply based on the fact you chose one route over the other. Thats as real as it gets and I think its important to know what your options are in both paths (MD or DO) so that an informed decision is made you know?