and if there is enough prior art out there to allow continuous requests you can bet the requests will go on and on... I would imagine tho that the law of diminishing returns would eventually begin to kick in as the prior art the third party requestors throw against the wall becomes less and less sticky.. that's when IMO we would begin to see rejected requests..

So in theory requests could go on forever.. but IMO the likely hood of significant prior art continually existing makes that possibility very unlikely

jmo.. corrections welcome