I had to think about what you're saying for a while because I'm so accustomed to having at least footers that I "didn't see" it. Yes, it looks like to be a trend.Speakers no longer sitting directly on the floor. Most speakers are now raised either on footers, a platform, or both.
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But I wonder, even if one dismisses the effect of whatever particular footer or stand may be producing or not, is it possible many manufacturers have noticed some advantage simply of raising the speakers off the floor to some degree?
As a father of young kids I welcome anything that brings stability. Not really a problem with these behemoths but making a bit more lean towers more stable is definitely a good idea.
Apart from that it depends on your floor. I've found extra stable footing almost always sonically beneficial. Nothing major but as I'd do it anyway it's good that it's not a downgrade.
I don't think speaker manufacturers have noticed anything. It's their design from ground up so they measure everything as is, be it with platform or not.
Or perhaps they have always known that sure footing is a must but the trend has been against it - people wanting smaller footprint speaker? And now we just luckily have a reverse trend which is technically better?