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.
Perhaps, with tongue in cheek, we could call this the p0 speed — as in it doesn’t make sense and it’s guaranteed that 0% of customers achieve it.
It's really really difficult to predict this statistically.
OTOH, there's a guaranteed minimum speed the ISP has to deliver.
If anyone wants to have an unfettered pipe then call up a Tier 1/2/3 ISP and ask for a commercial connection via a single-mode fibre, and be ready to pay quite a bit for it.
You might be surprised to find it surprisingly affordable. Cheaper than colocation, even.
If you get half a rack or less, that tends to be (quite a bit) cheaper.
Assuming you can easily get hooked up at a residential address. Perhaps if you live in an apartment/condo tower, then fibre may have already been run:
* https://www.fibrestream.ca/locations
Some random house, on some random street? Unlikely.
The community of Ammon, ID, built their own municipal fibre network because of this:
> It all began about seven years ago when the city government, suffering from horrible upload speeds, wanted a dedicated 100Mbps circuit between City Hall and the Public Works building, less than a mile apart. Qwest (now CenturyLink) didn't want the project, while Cable One offered to do it for a start-up fee of $80,000 plus $1,000 a month, Patterson said.
* https://arstechnica.com/information-technology/2016/06/what-...
At this year's (virtual) NLNOG there was presentation from a fellow who was fed up with slow Internet options in his rural Michigan county and so setup his own ISP by having fibre optic pulled to his house and then redistributing service to his neighbours:
Such rules are not within the American Overton window for the usual reasons.
[0] https://www.broadbandchoices.co.uk/ask-our-expert/broadband-...
I think the biggest reason they say "up to" is because a lot of poeple get a cheap $40 router that can't support that the advertised speed. Heck, I just moved into a new place that gives symmetric gigabit speeds. I had to replace my router to actually get one that can handle the advertised speeds (I had an APU1d4 with realtek ethernet ports that saturated at 300 Mb/s). My older laptop does not even have wired nor wireless speeds that can handle the connection.
So while I am no fan of a lot of ISPs, I completely understand why they say "up to", they don't want to deal with folks who say they don't get their advertised speeds while using a $200 laptop and a $40 router.
https://transition.fcc.gov/oet/mba/images/2018/chart1.png https://www.fcc.gov/reports-research/reports/measuring-broad...
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.
When I was on ATT gigabit fiber in San Jose, it was hard to confirm the speeds, but they would vary a lot more. I think most of the time at peak I would only see 400 Mbps down, but closer to the line speed off-peak. Upstream was more consistent.
Sonic gigabit in SF. I’d say that’s within margin of error. I see 900s on the early AM. Plus my WiFi can’t go that fast so I’m ok with it.
Granted, before my current router I was only hitting just over 50% of the rated speed. But that turned out to be the router I was using, its CPU was not fast enough or something. With a new router and all wired connections between me and the 'net, I get the speeds I pay for.