Having built more than a few subwoofers, initially I went the plate amp route. Primarily because they were cost effective and simple. I still have 2 older Daytons and never had any reliability issues with them. However, I did find one rattled pretty bad as I tested it long after I built it. I have also built boxes that have buzzed badly and more bracing was only ever able to dampen somewhat!
Now that I have more design experience, I avoid adding anything to a cabinet that might buzz or develop a buzz. When we are talking low frequencies at decent amplitudes, I have found that parts can vibrate or loosen and vibrate and you would not have known without testing with a frequency generator. While cabinets can be tricky, bolts, port tubes and drivers themselves can buzz at unexpected frequencies (hint: not just really low ones).
I also like the modularity that can be attained with separate parts for the cabinet. I can attain better cabinet integrity and get to optimize the amplifiers and electronic crossovers. While amps have mainly been a cost improvement, the advent cost effective dsp technology has made designing crossovers easier and allows tweaking of the design from the model or to fit room acoustics. I admit my approach has commercial challenges for most of the market, but suspect will some aspects adopted eventually.
I think it is noteworthy that the Apple Homepod attempts to adjust to its location. I expect that we will see more intelligence driven into speakers in the future. While I love to optimize my electronics, most of my family and friends just want it to be easy to use and sound “pretty” good...
Ww