With the recent IP Stipends being cancelled, there's no real way to get all the runes. However, it's been stated by Riot Blackrook that having all the runes is "annoying" and that there's no real need to have all, and he disagrees with "the notion that you need all the runes to test what needs to be tested."
That being said, what about when someone needs some particular runes to test something?
The best example from recently is Yasuo.
The rune bundle doesn't have crit chance runes, so what happens when someone wants to test crit chance or crit damage runes on yasuo?
Well, under the current system, they're out of luck unless they have the spare IP just lying around, which tallies up to 14,145 IP just for the crit chance runes. The crit damage rune set costs even more. Doubtless, there's gonna be another energy champ in the future, and so what will people do when they need to get energy runes? What if there's a champ that uses health regen, or is drastically improved by a full cdr page? The examples go on and on, but eventually, these runes will be needed to test specifics of a champion, and testers won't have them.
**So, my idea**
Have there be an item in the shop that instantly grants 10k IP. So you pay 10 IP, and suddenly you have 10k IP to buy a full rune set. With this, people can simply buy it when they need it so they can get those super specific runes as needed.
This way, people only get what they need and Riot doesn't have to worry about granting IP.