Is there literally anyone left on MacRumors that isn't rendered absolutely non-functional by purchase-based over-analysis? These threads are beyond painful at this point.
If you need a computer as tool to do work or to make money or both: Buy what you need when you need it for what you need it to do. Budget should reflect its potential to advance your earnings. The moment it is no longer able to do what you need it to do, then you buy what is currently available that once again meets that need. What is "on the horizon" makes no difference. You buy to put into production, to earn money or advance a hobby or set of tasks. Repeat as budget allows.
If you are buying Apple products as an Apple-user lifestyle choice: Buy the low-end, mid-tier, or high-end depending on your available free income. What it does doesn't matter because you're buying it to own it, not to use it to potential or against earnings. But don't buy beyond your means. The moment there's a rumor (or better, an event announcement) that is likely to highlight a replacement for what you own, sell it immediately. Before the new model is on sale. Once the new models are on sale, jump back to the beginning.
There's literally no other reason to buy a computer. None. I guarantee any purchase will fit into one of these two pathways, and by following them, leaves you immune to whatever release schedule shenanigans Apple has in store.