Well, according to http://www.paulgraham.com/startupideas.html you can literally go and find good ideas right now and every day thereafter.
It is also the basis of the Lean Startup Machine weekend (phenomenally popular).
You can train yourself to have ideas. Good is just an evaluation system.
People may indeed be incorporating a new product into their lives and the Founder will need to manage customer expectations and fallout. A high likelihood of discontinuance does not disqualify his attempts from being a startup.
The truth is, from a validation perspective the OP may have stumbled onto a supremely successful model of idea validation. Build it, tweak it, pump it for 11 months. The next project has 10 months. The next 9. Etc. Compare the metrics after one year and choose the most successful.
However, the statement that good ideas do not come up routinely and is false. They may just not be routine for you
inspiration: A sudden brilliant or timely idea 
If an entrepreneur trains via founding companies, then, should an architect train via filling the city up with half-arsed buildings? Nowhere in the pg article does occur something like “build random ideas into companies routinely”. Also, in that write-up is writ:
> If you're not at the leading edge of some rapidly changing field, you can get to one. For example, anyone reasonably smart can probably get to an edge of programming (e.g. building mobile apps) in a year. Since a successful startup will consume at least 3-5 years of your life, a year's preparation would be a reasonable investment. Especially if you're also looking for a cofounder.