Here’s the comment I made last time this idea popped up in a thread: Even if we were to adopt something like the Shavian alphabet, it would only work for a few generations at most until sound change and dialect divergence built up enough to once again strongly divorce spelling from pronunciation. Not to mention the fact that it’s impossible to come up with a phonetic* alphabet that accounts in a useful way for dialect differences, even just in American English. This has already happened with hangul, probably the paradebeispiel for successful intentionally designed phonetic systems: spellings that were once phonetic (though, again, in only certain dialects) have now become conventional due to sound change. So, in addition to the dialect problem, you’d end up having to either completely replace the alphabet again every hundred or so years, or you’d be right back where we currently are. Plus, interventions into the spelling system will a) make older publications harder to read without mass-translating them all into the new systems every few decades which b) will create reading difficulties for the generations that end up having to switch with each new update. Not to mention spelling things the way we currently do preserves etymological information (though imperfectly) about the words in question. Not to say our current system is perfect, but rather that any such system is arbitrary, and will eventually become conventionalized either way without active, persistent intervention that comes with its own significant downsides. *Used here in the lay sense, not the linguistic sense