This is not how it works. Just because the mining reward will shrink, it doesn't ensure price increase. If the miners can't pay their bills, they simply shut down their business. Block reward shrinking means pretty much hash rate decline on the long term.
Thanks for mentioning it out, as I was being too positive while writing the reply and forgot to mention the other side of this whole scenario which is bad for a miner. But you said, that's not how it works --> that would be in a way to emphasize the bad side of it, which is high hash rate means more machines and more energy, and more expenses. If it exceeds the profits then obviously the business will go bankrupt.
How can you say, it doesn't ensure a price increase, I mean, after each and every halving, back in time, the price of BTC improved and reached new ATH or isn't it? Maybe I am missing something. Would love to hear from you.
Just to be clear, I am not being too optimistic about the BTC price, and of course, I accept the possibility of BTC not touch new heights but the probability of this possibility is negligible in my mind.