How viable? More viable than the newer systems you mentioned, clearly.
When it comes to web applications tho, Django is not as pollished as Laravel/Symfony. There is no webpack integration (or any other npm frontend tool). built-in authentication is very basic, hosting is a pain.
The thing is a haven't written a single line of code in Django, but modern PHP and it's ecosystem looks more fun from a front-end, JS developer's perspective
Laravel is a great framework, but the tooling in PHP is amateur hour by comparison. The app ecosystem in Django is only comparable to Rails'.
Looks like maybe the ignorance goes both ways? People really underestimate the size and maturity of the PHP web development ecosystem and it's professional community, and there's no shortage of tooling to build and support apps on the language.
Django: 34,019, Laravel: 26,881, Rails: 9,300
https://github.com/topics/django
https://github.com/symfony/symfony
Modern PHP ecosystem is a shadow of their former self, in a positive way.
Even the top packages are pedestrian things like logging, event dispatching, sub-process management, and testing.
But PHP has a Microsoft-level of baggage, and those bridges can't be unburned.
Rails and Django are the pieces of web tech most likely to stay in the game.
It's pretty fast to prototype and then cut stuff you don't need.