Retainment has never been the issue. 90% of jobs in the military are basically office jobs to support the 10% who would actually see combat. And if you are part of that 90% you have a pretty cush life. Monthly tax free pay for food and housing, free health and dental, potential to live in Japan, England, Spain, Germany, Belgium, or pretty much anywhere else, 30 days of paid time off a year, gi bill for free college, the thousands of benefits vets get after they separate, a pension for life after 20 years for those who stay in, it's not hard to see why people stay once they're in. Where they are having a problem is that initial hurdle, getting people actually in the door. Which makes sense, a lot of young people, especially nowadays, are pretty anti establishment; there's also an obesity, drug, and mental health epidemic that disqualifies people from service, and there is always that looming threat that you could be sent out to die.

To answer your question, no, no meaningful standards have changed to allow more people in, besides allowing marijuana usage. Which was basically already allowed; you just needed to pinky swear to your recruiter you had never done it. If anything it's been made more difficult with new requirements for previous medical history.

Ultimately I'm glad I joined, the benefits far outweighed the negatives. It lifted me out of poverty to a job where I'm making 6 figures and got to see the world. Only you yourself can decide if joining is worth it.