It's a promising idea, but probably wouldn't help with drug discovery.

Horrible idea antibiotics are not toys and have side effects. Don't use elderly people for experiments when they are the one group least able to handle this.

You want to cause current antibiotics to be less useful so pharma will invest more? Just allow generic versions.

If you want to pressure the pharma industry use laws.

Every major family of antibiotics has generic versions, and that is not resulting in the needed discovery. This is probably because the vast majority of the "investment" required is in compliance with regulations that didn't exist when the currently-widely-used antibiotics were discovered.

Some antibiotics do have a good enough safety profile that such occasional speculative use would be a good tradeoff. Elderly people are also the one group least able to handle infections! Others do not.

Which antibiotics would you use?

I was thinking of things like amox-clav, cefalexin, doxycycline, and azithromycin, and screening the patients for risk factors. Oral antibiotics that are commonly used in empirical therapy (i.e., without cultivating a bacterial culture) and have low risks of dangerous side effects. I suspect that, for example, fluoroquinolones would be less likely to pass the cost/benefit test due to their more serious side effects.

> there would be an added pressure on the pharma industry to innovate in antibiotic development by accelerating the loss of existing antibiotic efficacy through the evolution of resistance

You're joking, right?

Total antibiotic resistance is what we're trying to minimise, remember. You're proposing to achieve that in the long term by making it worse in the short term, but the only way that makes sense is if there is actually an abundance of new antibiotics "out there" waiting to be discovered, and the binding constraint currently limiting their development is that pharmaceutical companies can't be bothered researching them. But that is obviously not true -- steadily growing resistance has raised alarm for decades, and any pharma company that could produce a genuinely new antibiotic today would make immediate bank.

IOW, the incentives are already there and they aren't helping, so why take the extra step of making things deliberately worse?

> accelerating the loss of existing antibiotic efficacy through the evolution of resistance

This is another one of those schemes for getting a bunch of people killed in the service of medical crankery, isn't it.