Well, most 100+ employee companies are probably older than the law. Other than that, your attitude is of the rather useless variety: it's easy to disprove, as just a single counter-example is sufficient.
I'm actually not even sure if the majority of US companies does /any/ business in foreign countries. Even among those 100+ sized, an awful lot of them are hospitals, regional cleaning companies etc that couldn't bribe any foreigners even if they wanted.
(edit: just noticed that I had missed the "sharing economy" qualification. You may be right in that context.)
Then, to take an example closer to this audience, there are all those that sell into foreign markets but have basically no contact with those markets other than what's mediated by their payment processor. Think of some medium-sized ISV: under which circumstances would they even get into a situation where bribery was an option?
Is corruption something that actually occurs in the US–to such a degree that a significant portion of white-collar employees know how it works? Because I've never seen it, and wouldn't know were to start.
The FCPA is actually among the rather great achievements of US diplomacy. Until its enactment, my wonderfully law-abiding home country of Germany still allowed foreign bribes to be tax-deducted. It wasn't that bribery itself was tolerated domestically–far from it. But they considered it a matter of pragmatism to adjust to lower moral standards in other countries. Of course such rules only perpetuated those "lower moral standards", and German businesses never were the powerless victims they claimed to be.
When the US started to enforce rules against foreign corruption against domestic companies, these had a strong incentive to lobby for similar standards abroad, and for the US to use their unparalleled power to directly enforce such rules against foreign companies as well. The result was the almost complete elimination of corruption among a segment of the economy, namely large internationals, and specifically their b2g business.