So my little question is this: is it okay to say that replacing calendar dates with block numbers could have an effect on how an investor thinks both in the short term or long term, when it comes to investment planning involving Bitcoin?
I doubt if it will change anything... Investors are likely to think the same regardless of if they choose to rely on block numbers or not. Although, there's some sense in what you're trying to come up with because I think it can practically work. If time practically acts as a reference that distinguishes the before and after of an event
(common physics definition), then block numbers can also do the same, especially with the main halving event that occurs after every 210,000 blocks
(approximately 4years).
But like I said, it won't change anything as Investors are likely to think the same way. In fact, most people probably won't understand the concept, so it's best we leave things the way they've been. There's no point of handing the work of time over to Bitcoin just to prove a point.