But there are so many wheels to invent out there, that in some cases it just isn't worth re-inventing one that is already "done".
Your not re-inventing anything you are just putting a chip and LED together, it is so trivial as to require no invention other than a google search.
You can use an NE555 oscillator and LED, or you can change the PWM frequency and just use an analogue write.
There must be modules with a simple single digital input which causes a beam of modulated IR to shine when the input is taken high?
I know people can be persuaded to buy almost anything but it is so simple it hasn't occurred to anyone that some people are willing to pay a premium for this.
I await the inevitable link that proves that some people are that cynical and that no one ever went bust underestimating the intelligence of the public.