I beg to differ.
Getting a locked in handheld without ability to modify/upgrade is not such a great future proof deal.
That handheld will be ewaste within 2-3 years I reckon.
Anyone who buys a gpu now will still be able to sell that for 50% value in 2-3 years. A handheld will hold no such value.
They are not "locked in", you clearly have not done your homework on the new handhelds and what they really are capable of doing. You can even side load games from other gaming platforms on the steamdeck and install windows on it too, also the steam os even has a full OS desktop so can be used as a full pc that way or as said install windows and will become a fully enabled windows pc handheld like the ASUS Rog, Lenovo Legion Go and all the other Chinese brand handheld pcs, huge market in handhelds right now. Go check the Legion Go and Asus Rog Ally and devices like that including the steamdeck what they really can do, also the AMD Z1 Extreme APU in the Ally and Legion Go are very capable cpus/gpus inside that apu and only going to get better on next APU updates coming around the corner too.
I have been looking a lot into a new handheld pc and the one right now that fits the bill for me is the Lenovo Legion Go (use will be not just for gaming mostly but applications that require a lot of cpu cores and a good gpu in a small device) but recently released and stocks are still difficult to get in UK and EU but released the end of October and stock landing in most UK and EU places was set around middle of this month so soon many will be about, the whole PC gaming on a desktop/laptop is heading very quickly to PC handhelds there is huge demand for it and why you are seeing more and more well known companies join in now and more to come for sure, the Chinese handheld brands lead the way at the really high prices as they were niche products and now becoming more normal/realistic prices for the masses to buy eg steamdeck,Asus Rog Ally and Lenovo Legion GO.
Watch how this market gets in the near future even none techies and nerds are all excited by it and want one of these devices or in some cases more than one.. Go youtube a bit about these devices and what you can do with them and I warn you ... You will want one too after it . Great devices and most exciting thing that has happened to PC gaming to the masses in decades. Remember I told you when you look back in just a few years and your collection of handheld PCs.