OpenAI is going to add it to Plus subscriptions. I.e. available for many at no additional cost. Likely with restrictions line N prompts/hour.
As for API price, when it matters businesses and people are willing to pay much more for just a bit better results. OpenAI doesn't take the other options away. So we don't lose anything.
IMO the 4o output is lot more Enterprise-compatible, the 4.5 being straight to the point and more natural is quite the opposite. Pricing-wise your point stands.
Disclaimer: have not tried 4.5 yet, just skimmed through the announcement, using 4o regularly.