Yup. They gave about three years of OS feature upgrades/updates, then security patching for more years.
This will mean different things to different folks.
Power PC Macs stopped at Leopard, but got security updates until about 2011 or 2012. Recently I came across the existence of a Snow Leopard beta for PowerPC, but it looks like Apple killed it. Why they did? Likely the strain of the development platforms: iPhone, Intel Macs and future devices like MacBook Air and iPad. It was just legacy they wanted to get rid of and business opportunity to get more upgrades.
Intel Core Duo Macs stop getting OS releases after 10.6; thats 4 years
Core 2 Duo MacBook Pro's which were launched in late 2006 went up to 10.7.
If you went with the third generation MacBook Pro (mid 2007), you got a run of (6) OS releases, stopping at 10.11.
Is there a chance Apple could do this with Apple Silicon? I don't think so.
The technical limitations were there partly due to switch to Core 2 Duo and later releases like 10.7 requiring a 64 bit processor. Unless Apple does something radical like bring 128 Bit computing the Macs. I can't see any practical limitations Apple could introduce in a few years to make a first gen M1 MacBook Pro obsolete.
If you look at the iPhone X for instance, which is a first generation design, there is no technical limitations preventing support up to iOS 19. It still works great for a four year old device. I expect the same for these Macs.
What will likely happen is rapid refreshes, so, impatience might work against you if you want the best bang for your buck. I wouldn't be surprised if by March '21, Apple updates both the Air and Pro with faster SoCs and newer four port models.
Keeping in line with 2007, there of course could be a third refresh in late 2021.
For me, it just doesn't make any sense in waiting and evaluating my needs and what I am doing, its not requirement to upgrade anytime soon. My true upgrade cycle is 2023, but with this purchase happening in 2020, I likely will not pick up a new MacBook again until fall 2025.
My recommendation, if you don't have any particular need to upgrade, wait and see how early adopters handle it.