My experience is different as I cannot discuss buy-ins and rebuys but I have cashed quite a few times. My breakdown of largest cashes (within a fair volume of final tables) indicates they constitute about 36% of my total cashes made.
However, I have simply followed my own intuition that it was vital to cash and the more times you cashed the more experience you would gain. With that experience you then start to ladder more frequently and attain the larger cash positions.
If that was my approach already it was underlined by a pro who stated one of the most important habits he had developed as a pro was to cash regularly. He realized that you could never play buy-in catch up over the longer arc with the big scores you might make. What you need to do was recoup your buy-ins regularly and then run deep as well.
Quite often I will run across some info about a pro and will check their Hendon Mob or a similar stat site. In nearly every case the number of cashes they have made blows you away. Try it yourself. As one example, I recently heard about an individual who was a very solid pro with online earnings of US 4,000,000. Yes he had some deep runs and largish paydays but it was his ITM stats that blew me away - still fairly young he had cashed in over 4,000 tourneys.
If you look at such stats you will frequently find pros (the majority) will have an impressive number of tournamentt cashes.