I’m sure if you think about this a little bit you’ll see that preventing the sale of businesses is a terrible idea.

Please feel free to elaborate.

Wouldn’t one generally expect someone proposing a fringe/seemingly absurd idea to do the “elaboration” in the first place?

I'm not a fan of how acquisitions are often used, but how would you go about making them illegal? Would an entrepreneur be required to maintain ownership of a business and its assets forever?

Make it so that shares of a company cannot be bought and held by corporations. Make trademarks non-transferable; they can only ever be owned by the entity that originally filed them. Make copyrights/IP rights subject to public auction; any time that ownership of a copyright would be transferred from one company to another, the public has the right to bid on it collectively, and if they outbid the company then the copyright goes into the public domain.

None of that prevents aquisitions.

Companies would just be bought by wealth induviduals (or trusts, or whatever) as opposed to companies, and copyright/ip would just stay unde the original legal entity and licensed out.

Great, that's an improvement.

How?

You’d just have a bunch of under the table deals with similar outcomes but much less transparency.

Also effectively you’d have way less economic growth and paradoxically less competition.

For instance entering a new market which is dominated by oligopolies would be prohibitively expensive even if there is a lot of potential for disruption. Now you can just buy a small/ailing/mismanaged company and restructure it. With you proposal everything would have to be built from scratch at best you could just buy some of their assets during bankruptcy proceedings.