Single Mode or Multi-Mode?

[Baldy's Boss]

TT lets people work with rail,road,air,and sea transportation...but what are people's feeling about diversification vs. specialization?

I typically run a "pure play" railroad...I have in the past made I think one attempt each starting a bus company and an airline but never got far with them.

On the other hand,in the past (though not recently) I have bought out the more successful of my AI competitors,which may not share my scruples (or within railroading may not share my bias against diesels and monorails)...in these cases I typically neglect the non-rail operations but let them run with rare interventions.

I'm interested in the philosophies of other players as I grapple with a competitor that has endured over 40 game years and overtaken me in performance rating...a road hauler with four times the number of vehicles as my railroad but I have over four times their revenues.In a couple of cities their drive-through bus stations block me from extending platforms deeper into the city to increase catchment of my street-replacing stations (I'll bring trains right outside your front door!).

If I buy them and pay off their debt the merged company should be strong,but the complexity of being a multimode operator is something I usually avoid.How do others feel about being or not being specialized?
(I made a couple of attempts to have railroads that only did passengers or only did coal hauling but those likewise didn't particularly succeed).