> The problem with this approach is that the law will always be lagging behind. It is not fair to change the rules during the game.

Why is that a problem? Why would we want prescriptive rules to be formulated in advance of the reality to which they're meant to apply being fully understood?

> Therefore, the only solution is to ensure people act according to the spirit of the law, not the actual law.

Which is something our actual legal system already does fairly well, precisly because it doesn't overemphasise technical, instrumental details, and applies broad rules to intentional conduct in an often form-agnostic way. For example, anti-trust laws about collusion and price fixing wouldn't care about what specific communications medium was used to coordinate collusion, apart from validating the evidence that there was indeed collusion.

In this case, I think the mistake you're making is in thinking that restrictions on the introduction of new technologies based on the long-term effect they might have on demand for particular services in the overall economy is something that is within the spirit of the existing law. It isn't. It never has been.

People have certainly worried about how new technologies would impact people's earning power over time, dating back centuries to at least the era of steam engines and railroads, but that's never translated into any legal framework allowing for restraining the development of new technologies. Anti-trust law has nothing to do with it, and the spirit of the law behind it has always been aimed at protecting consumers against market manipulation, not protecting employees against reduced demand for their services.