Should the groom thank his ushers in his speech?

It's polite to thank them yes, it's common practice for the groom to thank the ushers and the bridesmaids.

he doesn't have to make a speech, he could simply choose to toast his new bride... he could make a thank you speech at the rehearsal dinner if he wishes, thanking his ushers/groomsmen and friends and family...

no... that's for the bachelor party or some other time...

Doesn't have to, but would be nice.

You can thank them. It's 2017. No one is going to whisper about how that's not typically done. However, your speech should be succinct. Guests are giving you their undivided attention, pausing from their drinks, and I think everyone has a shorter attention span these days... so you should just sum this up, such as by saying, "I want to thank all of my friends, including my groomsmen and our ushers today, for their constant friendship and support." It may mean more to them to thank them privately before the ceremony. Also, a tradition is to give a small gift to your groomsmen, so you can extend that to your ushers with your sincere thanks. Your speech shouldn't be more than 2 minutes long. Definitely practice. That will be time well spent! Congrats.

The groom doesn't normally make a speech.

However, if you want to thank your wedding party as a whole which will include them. You need to keep a speech short & simple otherwise you lose your audience.

All the weddings I been to, the groom does not make a speech.

Sometimes at the end, the groom with the bride next to him, thanks all his guest.

Most people that make speech's, they are about the couple.

Really should only be a toast by the Best man and sometimes MOH.

No. That's for the bachelor party or some other time.

No. The wedding speech is meant for the bride.

Of course