I don't fly internationally all that often, but I do sometimes and just did this week, and I have never had an immigration experience that took longer than the baggage claim did. Is this a problem that only occurs at airports other than O'Hare, or am I just lucky?
The big variables are (rough order) entry airport, the mix of passengers on the exact aircraft you're on relative to your own citizenship/immigration status, the general business (or lack thereof) when the flight you're on gets in [+], and conditions at the airport on the day of your arrival.
If one very consistently flies exactly Delta 6 and is a US citizen, one will very rarely wait more than 15 minutes in Detroit.
It is, unfortunately, very, very easy to spend hours in line. (4th quartile for me is probably 2 hours; max was close to 5.) If one is selected for secondary screening, throw all estimates out window; you've transitioned from routine travel into an adversarial proceeding with the USFG.
[+] Since most airlines operate on schedules which do not change much on a week-to-week basis it is fairly predictable that e.g. 10 AM on a Tuesday, and hence $BAR Flight $BAZ's scheduled arrival window, will be busy, given that N flights from abroad arrive near that window.
Its been a few months since I've cleared at O'Hare vs Midway. But my memory is "long ass immigration line that is bad for US citizens without Global Entry and terrible for non US citizens" followed by baggage claim and "basically a cursory scan by customs".
The last time I did this I had Global Entry and 5 of the 10ish kiosks were broken so that took a fair bit of time as well (you skip immigration but not customs in that case).
[edit] the time I had a truly miserable experience the line for immigration stretched long down the hallway to the immigration hall. It took more than an hour to see where the citizens vs non-citizens lanes began.
You're correct in that we can't offer immigrations/customs help in US airports (with the exception of JFK and MIA). However, we can help in about 400 airports around the world. We can expedite clients through departures on international flights.
A lot of our clients flying domestic, however, still find value in the service especially families and the elderly.
Wow, that kills your arrivals product in the US then. $375 for someone who will meet me with a smile, watch me line up for immigration and carry bags? An interesting tidbit is that Japan Airlines offers a similar service for free for familes: https://www.jal.co.jp/en/inter/support/family/
Interestingly I tried both those airports as they're the ones I most frequently arrive at when flying in to the US. I'm not a US citizen, and the lines for immigration at both of those airports take me a couple of hours usually, so I'd have happily stumped up for this service. The quote you offer for both says they do NOT include expedited immigration/customs however. So is your site broken already or what?
Edit:
I see from other comments in the thread that you do this at JDK/MIA by having one of your agents stand in the queue ahead of your customers and then letting them cut in when they arrive. The British in me finds this abhorrent, and there's no way I'd do it.