Yes, but not typically beyond the level of hardware that was available at the time of purchase. So if you buy a high end laptop, then job done.
GPU upgrades are possible with MXM card equipped systems, but that is horrendously expensive and you usually have to wait for GPUs to become available. I think XoticPC was selling GPU upgrade kits for some of their models a few years back.
But then you run into the dilemma of mixing a faster GPU with an older CPU.
If you think about it the chassis, battery, screen are the 'cheap' parts. Changing out the guts is the expensive part.
Really only two options. Buy a new laptop, sell it when new hardware is available buy that. Basically that will cost you the difference in price every time you...