* A massive bulk of flex rates is different price than a single flex ticket
* when I travelled to a single city with 20+ colleagues for several years, our nightly hotel rate was less than quarter of published rate. I don't think we got anything like that on Airlines, but nevertheless, bulk gets discounts.
* I forget details but between specific frequent cities which had hourly flights, we had full flexibility and we used this all the time. So we might catch a flight hour earlier if there was one available, or hour later if need be than booked.
Basically to everybody's point, business travel is very different than vacation travel and intuition from once a year personal trip don't apply.
* Hotels are required by law to have a published "rack rate" and it's common for both leisure and business travelers to book at more than half, or more, off those rates. Airlines don't have that.
* Yes of course there are negotiated discounts for major corporations- but full flexibility is still far more expensive than restricted tickets, just like business is still far more expensive than economy.
* Most airlines offer guaranteed same-day changes, or at least priority standby, to high-status loyalty members (which most consultants are) so buying full-flex tickets to get an hour earlier/later flexibility is redundant - basically, paying for a benefit you already have.