Because there is an upper limit (from my understanding) of the number of Bitcoins that can be created, their worth will still multiply by 10 or 100 or more, IF

Because there is an upper limit (from my understanding) of the number of Bitcoins that can be created, their worth will still multiply by 10 or 100 or more, IF they exist and grow as planned. Splits only increase that value if you own pre-split.