The authorities, of course, would want to catch the person at the top of a criminal enterprise. (Unless they are corrupt and are paid to be lax and inefficient.)
Yes, you would think that would be the case but in my research into river pirate crime in the late 1700's, using mainly the Records of the Old Bailey, I found that 89% of those found guilty were Lumpers, Watermen, Porters and Fishermen for petty amounts, while the Copemen (what we would now call a fence) and the gang leaders were left untouched. Only one Commander of a ship, one toymaker and one liquor shop owner are found guilty despite the toymaker and liquor shop owner accounting for most of the goods stolen in terms of value. The poor were stealing small quantities of sugar, coffee, tea and such (which were worth much more than they are today but still tiny in proportion to the total theft value.)
This was despite there being 12 factories in Wapping alone, receiving the stolen goods, processing and repackaging them, and selling them on.
And yet the poor in manual occupations were also more harshly punished with sentences of hanging or 7 years transportation. The Commander received 12 months imprisonment and a fine for his involvement in stealing silk cloth. Those individuals who actually stole the silk were all executed. The liquor shop owner was transported for 14 years for receiving goods, but the toymaker got only a year’s confinement.
When you compare their ages, the trials do not demonstrate hardened criminal masterminds, but rather they show young men aged 20-24 with poor judgement, lead astray by older men who should know better. However, young men have always committed a disproportionate amount of crime, just as most crime has always been petty crime and opportunistic. So, little has changed in that respect.
The point of my research was to dispute the effectiveness of the Thames River Police (the first organised Police Force in the world) and despite the claims made, it was the building of wet docks on the Isle of Dogs with high walls that solved the problem. These removed the delays associated with the tide and insecurity of the cargo. Cargo could be unloaded throughout the hours of daylight without being left on the quayside.
The effectiveness of the River Police was more as a deterrent than as a detective or prosecution service, as was more the case with the Bow Street runners.
Of course, it may be different with land-based crime, and with medieval thieves guilds. I haven't researched that so I can't say but it is really no different today. I don't wish to get political as we aren't allowed, but look at the amount of effort put into investigations and prosecutions for benefit fraud compared to tax evasion. The former is likely to be hundreds of pounds, while the latter could be millions. So, I'd doubt that it was ever different.
I'd agree with the
@The Judge 's conclusion, that the leaders were well known to the authorities but were too powerful to be prosecuted.