Not really a 'thing of the past since there are still many altcoins out there that had their own client wallet. To be honest, back then I used to think any new altcoin without a proper client wallet is trash and shouldn't invest in. Can't blame me since it was the days where many ERC20 tokens with very lazy and low effort dev so we had to have some standard back then.
But things change and so with some already point out in this thread, the inconvenience and risk of many wallets dwarfed by the convenience on one in many ecosystem.
Majority of them are trash yet it becomes dead for a few weeks or months specially to those who had staking feature excluding into those coins which are old and had that liquidity or demand.
Of course, there would be changes as the years passed since technology is progress and new ideas do come out then it would really be just normal to have these kind of improvements
or changes and i do see it is way more much better than with the previous one but i do agree with those nostalgic feeling if ever we do encounter those back again
even though on small chances because most of things had changed up.