But at most there would be a delay of a few years in diagnosis if they are more prompt about it. No one goes too long with an untreated HIV infection before symptoms become noticeable

> No one goes too long with an untreated HIV infection before symptoms become noticeable

It's not that simple: The chronic phase of HIV is frequently asymptomatic, and frequently lasts over a decade[1]. Even the AIDS phase can last for years before an opportunistic infection causes severe enough illness.

The initial (acute) phase has flu-like symptoms that people typically ignore.

[1]: https://hivinfo.nih.gov/understanding-hiv/fact-sheets/stages...

Granting a decade long delay in diagnosis of all heterosexual HIV+ cases vs instantaneous diagnosis of homosexual men, the disparity still doesn't explain much - unless there is orders of magnitude shifts in the infection rates among heterosexual people over that time period.

> unless there is orders of magnitude shifts in the infection rates among heterosexual people over that time period.

There are two forces at play: decreasing infection rates among gay men, and increasing infection rates among straight men. Both aspects of the curve are "doing work" to change the statistics.

But yes, there are significant shifts that explain these changes: increases in IV drug use, a decline in condom use among straight sex partners due to readily available alternative prophylactics, and an overall increased emphasis on testing the entire population for HIV/AIDS.

> There are two forces at play: decreasing infection rates among gay men, and increasing infection rates among straight men. Both aspects of the curve are "doing work" to change the statistics.

You may have missed the point — only one of those is modulated by (relative) delay in heterosexual diagnoses post-infection.