And, the South African Large Telescope (SALT) has a single (spherical) 11 meter mirror(!). There are restrictions on what it can do. Try and wrap your head around this description:

SALT has an 11m diameter spherical primary mirror with an optical axis tilted to 37 degrees from the vertical. It can rotate through 540 degrees in azimuth. Positioned ~13m above the mirror, is a tracker and an optical payload, looking down at the mirror. The tracker moves across the mirror on a virtual spherical focus surface, allowing sky-objects to be "followed" as the earth rotates, without adjusting the azimuth angle for a period of up to two hours. This gives the telescope an annulus-shaped observing area in the sky, 12 degrees wide between declination angles of approximately -75 degrees and +10 degrees.

The expensive thing about telescopes is tracking. The 'mount' is more expensive than the mirror. That's true for a back yard imaging scope. It's true for the Mt. Polomar "big eye". It's true for the HST (launch costs). So, the SALT does some things to make the mount cheaper at the cost of reduced viewing.

The podcast didn't talk about interferometry. There's the Mt Wilson experiment. There's the Keck. There's the VLT.

For space based infrared, the idea that Spitzer has a finite supply of helium for cooling wasn't mentioned. The scope will be functional, but with reduced sensitiviy when it runs out. But what about the James Webb?

Then, there's the HST. It has done infrared and ultraviolet. The fine guidance sensors can be used for science, not just guidance. Also astrometry. But the side to side wobble of a brown dwarf was measured - side to side from an orbiting object. Very cool. Several whole shows could be done on the HST and it's various instruments. Probably true for some of the other big instruments - Keck, VLT, the Hale. In fact, my astronomy club just had an hour talk given about the Hale.