You think they are going to go backwards in terms of quotas like this, in the future?

Right...

Anyway, this is a welcome change. I've bumped into the 20 MB limit a bunch of times...

What do you mean keep? Once they release this 50mb limit it's pretty much set in stone forever as other email providers will assume gmail users can accept it. If they removed/lowered it then emails would break.

What do you mean by "emails would break"? They would be rejected by Googles MX servers, and the sending server would relay a bounce message to the sender explaining the problem... That is just a normal function of email.

All MX servers have arbitrary limits. Those limits can be increased/reduced at will without "breaking email"

It is already a common case that people send emails which are larger than the receiving system is willing to accept and are therefore rejected. They then receive a bounce and make alternative arrangements for transferring the file.

The pure market share could have been a motivating factor for parent post. I assume that things behave differently when you're the #1 at something.

However, this seems arbitrary enough to not have that effect.

They would sunset the feature and migrate all attachments to Google Drive, I think they did the same with Picasa and forced a move to Google Photos (I might not remember the product names correctly, I didnt use it but family members did)?

Gmail Attachments already count toward your drive space.

So, it is a what move to fill it up with mails.

Wow, that's good to know. It looks like one step before the force on more to Google Drive