>- Why was the Maryland State Attorney so keen to continue with the prosecution, despite a hostile witness?

Speaking in generalities without knowing Maryland's state situation specifically, but whereas US Attorneys (federal) are executive positions (nominated by the President and confirmed by the Senate), state level is (including Maryland) an elected position (you'll note the author mentioning voting for one of them). So politics ends up playing some role in that they want to get reelected, so be "tough" on certain causes of the day etc. Britain has plenty of history of that too fwiw. Prosecutorial discretion should play a role but it's not always pure. That said this was probably nothing special, merely in the same category as minor thefts, where if someone was guilty it'd be some sort of plea. Very bad to be caught in the grinder, but no sort of conspiracy. Someone complained of a small crime, state didn't do a good job with it.

>In general, why do individuals and companies appear (to an outsider) to have so much influence in the USA to 'press charges'? From a theoretical perspective, it doesn't seem like there is any advantage to the criminal justice system in allowing people to persuade the prosecutors to open a case, since a large company like Comcast could churn out hundreds of vaguely plausible but socially inconsequential claims of fraud, when the prosecutors could surely find better things to spend their time on.

This is a weird statement. In the majority of cases who else would you generally expect to kick off a case but the victim of a crime? It's always up to the government whether to start (or stop) a prosecution, but we thankfully do not live in a panopticon and thus the biggest source of starting criminal trials is... people reporting crimes. Prosecutors do have limited time and resources, so what they choose to pursue is going to depend on a lot of calculations both sometimes unreasonable and often completely reasonable. Whether what they pick is the best use of their time or not is not a trivial question. And again, Maryland AG is an elected position, so if people were angry about them going after cable fraud at all they'd be free to campaign against them on that.

>- Why is it possible to attempt to 'avoid being served' at all? I can't see anything wrong with receiving the notice by mail like any other correspondence.

Millions of people have no permanent address, or may only check their mail once in a long while. Mail sometimes goes missing (for weeks, months, or permanently). We're talking criminal prosecution here though even civil suits are no joke. It is an absolutely vital small bit of justice vs the opposing party (and particularly the vast powers of the state) to at the very minimum ensure people absolutely know they are being sued. And in turn have a chance to muster their defense, meet court deadlines and so on. There are reasonable safeguards if a court decides someone is purposefully evading, but there is a bar there.

>Are police officers in the USA really expected to just drive around as glorified (and armed, for that matter) postmen for the prosecutor's notices of petty criminal charges?

Yes, and the government can suck it the hell up. There are also professional servers who can be hired. But reasonable efforts must be expended to ensure someone being prosecuted or sued has been given adequate notice of that fact. The flipside is abuse of default judgements, which is far, far worse.

>- Finally, and, for me, most importantly, how could the author have acquired a criminal record from a case that was dropped prior to a trial, let alone a conviction?

They... couldn't? Author clearly is not a lawyer and was confused on something there. Maybe they're talking about some sort of credit report Comcast had filed as well. Or they just wanted the court records sealed (they mention getting spam mail pretty fast) or I don't know. But they weren't convicted of anything and thus had no "criminal record".

>I'm under no pretence that my own country's judiciary is perfect, but it appears to me that the USA has a number of bizarre procedural bottlenecks that could be fixed with little more than a stroke of a pen.

I could pick a handful of cases from British history going back decades and draw broad conclusions about the entire country as well and it'd also be silly.