BOA's are replaceable. And have a lifetime warranty.I have an older pair of Pearl Izumi Boa shoes. I like 'em but the "string" is starting to fray. I would love 'em more if there was a way to replace the BOA part.
BTW, velcro from my Sidi's (from the 80's and 90's) can easily be replaced by my local shoe cobbler for less that $20.00.
And the Boa company is great to deal with (unlike a lot of bike related companies that offer warranty and replacement parts in theory but are essentially useless when the time comes because they'll either the call it "ordinary use" and don't honor the warranty or have stopped making the part). I've broke a few boa's and replaced a few and one quick call they were in my mailbox days later. Pretty easy to replace too.