There's something to that - especially since RAM price-per-MB is no longer plummeting the way it did in the 80s and 90s. If a new application comes along that needs twice as much RAM, the odds are that it will
also need the latest CPU and GPU advances, too. Also, low-power LPDDR RAM only comes in surface-mount packages and just isn't upgradeable - there's no equivalent of the DDR4 DIMM stick that you can just plug in. The M1 has also turned having the RAM embedded into the SoC package with the shortest possible connection to the CPU into a performance gain.
Also, Apple are a bit mean with RAM, often low-balling the entry-level module with something like 8GB - which
should be enough for "entry level" users but - if you look at the prices of RAM in the general IT market - looks a lot like false economy. Apple have always charged a
ridiculous amount for their BTO RAM upgrades - most obviously when you look at the Intel Mac Mini and former iMac which took bog-standard DDR4 SODIMMs that you could get at a fraction of the price
retail (i.e. a distributor was eating hot meals and sleeping indoors on the profit margin) from a third party. E.g. with my 2017 iMac I
added 16BG to get 24GB for substantially less than Apple wanted for a mere 8-16GB upgrade.
The real sticking point, though, is SSD, because the flash memory in SSD is
perishable - it can only be written to a limited number of times before it degrades. Although the limit is fairly huge and should be enough for it to outlast the computer under "normal" use, it is always conceivable that a software problem will prematurely "age" it. Also, the reliability
comparison is often between a SSD drive and the mean-time-between-failures of a mechanical hard drive, which is a pretty low bar - nobody in their right mind would design a serious computer where you couldn't replace the hard drive.
The removable SSDs in the Studio are good news if only because it means that a failed SSD will be replaceable without a whole new logic board (as on the MacBooks) even if that has to be done by Apple.
...and Apple will need to provide a way for regular users to "register" the new SSD with the M1's controller. Apple
do offer DIY SSD upgrades for the Mac Pro (at their usual reassuringly expensive prices),
but you need a second Mac and Apple Configurator software to do it, so it is entirely down to Apple.
I don't think OWC have produced any SSD upgrades for Macs released since Apple switched from standard NVME interfaces to having the controller in the T2 chip (and then in the M1 SoC) - although that's kinda moot for MacBooks which switched to soldered-in SSDs about the same time.