The emergence of multi-modal travel search engines has so far not really attracted the large players in online travel... for now.
Brands such as Rome2Rio, GoEuro and RouteRank have certainly not been particularly stealthy about their operations - either having vocal founders or raising piles of capital.
But the concept of providing search results for the entire length of a trip (flight, bus, rail and other ground transportation services such as taxis) has largely been ignored by the likes of Expedia and Priceline Group (owner of Booking.com) as, presumably, not being core to what they do extremely successfully.
A year ago, European online travel agency group eDreams Odigeoadded multi-modal tools to its Liligo metasearch engine. But the others have been fairly silent.
Still, this is just one side of the equation.
For those that are running these still reasonably fledgeling brands, there are other issues to contend with.
Rome2Rio executive chairman Rod Cuthbert believes that if such as service was starting now, in 2017, gaining any form of visibility to the wider market would much harder than it was when his company and its contemporaries were starting out.
The slow decline in SEO as a tactic has made it "extremely difficult" for any new consumer-facing brand to get traction, he says, meaning that Rome2Rio and others will, at some point, reach a plateau of sorts.
Speaking at the EyeForTravel conference in London this week, Cuthbert says the hard work behind the scenes in securing relationships or getting content from service providers, such as rail and bus companies, has been done - some of it manually, some of it through technical connections.
But he warns that scaling-up further (Rome2Rio currently has around ten million unique users a month) will need something else at some point.
He says:

"We can grow to a certain size but then a change in shareholding is probably on the cards."
While this is not exactly a "come and get us" plea, what he is saying is that one of the large players will be needed at some point to really take note of the multi-modal opportunity and give one of the providers a bit of a leg-up.
A combination of marketing muscle and resources could help take businesses that have started well, got an audience and have important relationships to the next level.
And while the spectre of Google hangs over everything in the consumer-facing world of travel, perhaps it is the search giant itself that also takes note - rather than multi-modal being solely an OTA or metasearch play.
NB:Multi-modal travel image via Pixabay.