Nowadays all my emails are from the browser(gmail,outlook,etc), I used to be a thunderbird user and liked it, just wonder if the 'traditional' email client user

Nowadays all my emails are from the browser(gmail,outlook,etc), I used to be a thunderbird user and liked it, just wonder if the 'traditional' email client user base will be further in decline? To me the browser is the thunderbird, not as powerful, but good enough for normal use.