What do you mean by "can't do that"? I'm using the Vivaldi browser here and it doesn't offer that facility. Neither do Firefox or Chromium. I'm wondering if the browser you are using no longer supports this, either.

I don't think the presence or absence of a "mail link to" is anything to do with which email client you are using. The browser has to support it. So, that takes me back to what does "can't do that" mean?

With W10 and Firefox, selecting File/Email Link... in FF launches a TB message with the URL in the body of the message and the page title as the Subject. With IE, Page/Send link by e-mail... or File/Send/Link by e-mail does the same thing. With Edge, you click the Share button, but it only connects with the Mail app.

With W7, it works the same way here with FF and IE. If it's not working for your W7 system, open Control Panel, Programs, Default Programs, Set program access and computer defaults, select Custom, select Mozilla Thunderbird for 'Choose a default e-mail program' and check 'Enable access...', OK.