Looks like the OP has already made up his mind that a new table is in order, a high mass non suspended type. Actually I own a table that meets that criteria, the Galibier Audio Serac, and actually my previous table was a Teres Audio 225 which was another high mass non suspended table. So I have a small amount of experience in this arena.
Up until a few months ago, I would have been unfaltering in my support for a modern high mass table. Don't get me wrong, I truly enjoy my Serac, it is a wonderful table. The Pete Riggle String Theory 12" wood arm is a beautiful tone arm, and the ZYX 4D cartridge is a fine fine cartridge.
But last year I found a Thorens TD124 in a friends garage. I performed the basic maintenance to it, did some refinishing, and found an ADC LMF2 arm for it. I ran through a few MM cartridges on this table, as it was supposed to be my beater machine for playing rock and roll or pop records. To basically keep the hours off my ZYX.
Well this month I received a Clear Audio Signature cartridge that I had in for retip, and just to verify it worked and to hear it, well I installed it on the Thorens. The ADC is really not the best arm for this cartridge, but it is good enough for the time being. What I found is a very direct and expressive analog rig! There is something enchanting about this uncluttered and intimate presentation, that is different than my Serac, but still as involving. I have been listening to it for better than a week, and it is still very pleasing.
Now there are a few upgrades or updates for the Thorens that might up its performance. I need a new top platter as this one is dinged. I may end up buying the Applied Fidelity aluminum/Delrin mat for this table. Or perhaps the SMH/Tech acrylic platter mat. I do need the upper platter to provide shielding between the cartridge and the iron platter. The stock one appears to do this just fine, so I know it can be done, at least with the Clear Audio. I also should pull the thrust plate for the bearing, and just replace it. I may also consider buying the Applied Fidelity bearing assembly also, which includes a sapphire thrust plate and a ceramic ball bearing. Jim can release the stock ball from the end of the spindle and install the new one. Then comes the question if a higher mass plinth is needed.
Anyways, if one can buy a TD124 in good condition for $800 to $1000, and possibly put a few more hundred in updated parts in it, well the total cost could be $1600 or so. That table may very well go toe to toe with my Serac, which sold for $3.2K and was discontinued because production costs had risen to steeply.
So I cannot say for sure that a modern high mass table is going to outperform a vintage high mass one. I used to think that would be the case, but the Thorens has kind of thrown a monkey wrench in that. I do know that I am going to enjoy the project of sorting out the 124. I also know i love both of these tables, and feel very fortunate to own them. Hope you can find a table that meets your expectations.
Perhaps a table from Acoustic Solid, Teres Audio, Transrotor, or even TT Weights....I her they are building a new idler wheel table.
Regards
Mister Pig