Earlier quoted context omitted.
There's a solid technical reason for that though, as ISPs have no control over the performance of your connection's remote part. Sure, it leaves plenty of room for abuse, but this is a necessary disclaimer, not some slippery marketing.
Does anyone in the US actually get the “up to” even plugging directly into the ISP provided modem at off peak times?
Now, I absolutely would love to see it mandated by law that somewhere upfront in ISP info to consumers it's required to have a standardized SLA. A consumer-level SLA for sure, but still have it formalized and cover all of the basics. So not just absolute max bandwidth, but 90%/50%/whatever bandwidth, any guaranteed floor, 90% latency, any data caps, any throttling criteria, etc. All categories the same and measured in a mandated standardized way so universally comparable. I don't expect data center level SLAs at all, but there isn't any reason there can't be that level of clarity.
But residential/SOHO and such service inherently has more uncertainty and more compromises and capacity multipliers to meet lower prices. I think that's ok, just that it should be laid out and not buried in some fine print or support page in the disused lavatory defended by a leopard either.