I used to date a doctor that had many doctor friends, some of which were somewhat involved in creating the treatment guidelines (or something like that, I can't remember the exact details) for the NHS (the UK's national health service). I remember probiotics were specifically discussed and I asked why they weren't prescribed with/after antibiotics.
The answer was that it basically comes down to the fact that there is not enough evidence that supplementing probiotics orally does anything beneficial in the grand scheme of things. The amount of evidence that shows they do nothing beneficial or are slightly negative out-weighs the body of evidence showing that they are beneficial.
Obviously, if they work for you then keep doing what you're doing. But if people are wondering why prescribing probiotics isn't the norm, that's why.
Note: my information is around 8ish years old at this point, but I did a quick search before writing this comment and found a metastudy published in 2023 that seems to confirm nothing has changed.
The answer was that it basically comes down to the fact that there is not enough evidence that supplementing probiotics orally does anything beneficial in the grand scheme of things. The amount of evidence that shows they do nothing beneficial or are slightly negative out-weighs the body of evidence showing that they are beneficial.
Obviously, if they work for you then keep doing what you're doing. But if people are wondering why prescribing probiotics isn't the norm, that's why.
Note: my information is around 8ish years old at this point, but I did a quick search before writing this comment and found a metastudy published in 2023 that seems to confirm nothing has changed.