Do you think they are now a must have in just about all web sites?
I know rankings are not affected if you don't have a responsive design, so it still isn't a crucial thing and visitors to a website don't care about it, they just want to be able to see the content. It's pretty cool to have a responsive design, though.
Ranking are affected if your website is not mobile friendly. I guess it's been almost 2 months now since the update has happened.
Yes it is very important if you want a better organic results in SERP google prefers mobile friendly website first to rank higher
on serp
Yes, Nowadays responsive design is most important things for online business.
Yes, It's very important.
The .htaccess file is a powerful website file that controls the high-level configuration of your website. On servers that run Apache (a web server software), the .htaccess file allows you to make changes to your website's configuration without having to edit server configuration files.