I think you're overestimating the rationality of this game.
The reason why I avoided this term is that in Germany, there exists a quite strict of whatx an engineer (Ingenieur) is, which is defined in the laws of many federal states (Ingenieurgesetz [engineering law]). "Ingenieur" (engineer) is a protected professional title:
> https://de.wikipedia.org/w/index.php?title=Ingenieur&oldid=2... (*)
Falsely claiming that you are an Ingenieur when you aren't (by the definition in the Ingenieurgesetz) is a punishable crime in Germany:
> https://de.wikipedia.org/w/index.php?title=Missbrauch_von_Ti...
There exist some boundary cases under which as a software developer you can call yourself an "Ingenieur", but you have to be insanely careful about whether you actually satisfy the legal criteria (see (*)) - in most cases you don't and you are thus a criminal if you do.
If so, is this ever enforced?
Using the German translation "Softwareingenieur" of "software engineer" on your LinkedIn page might easily get you into trouble.
Typically, as far as I know, law enforcement agencies only get active in the punishable act "Missbrauch von Titeln, Berufsbezeichnungen und Abzeichen" [abuse of titles, occupational titles and emblems] if the culprit gets denounced by someone or if there is a public interest, but everybody knows how easy it is to make enemies in your job or on the internet.
Having a successful business requires a lot of factors that don't really have anything to do with software engineering. Things like luck, connections, access to funding, good marketing, etc. And while have good engineers on the payroll undoubtedly helps, the good engineers aren't necessarily the ones getting a big fallout from the acquisition and may not stick around for long after the acquisition, especially if they get put on a project they don't care about.
What's the difference between a software developer and a software engineer?
The honest answer is that in most day-to-day contexts, the distinction is more about company culture and title preference than actual job duties. A "software developer" at one company might do more rigorous engineering work than a "software engineer" at another.