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This is incorrect. You can easily do small scale work with almost all SMT components without solder paste. Solder paste is required for automated assembly processes. But almost anything done by hand can also be done with conventional solder.I disagree. I don't consider 0603 passives and TSSOP packages "modern" anymore. Of course these components can be hand soldered with ease (possibly at top quality with the aid of a microscope). Unfortunately, the industry is gradually abandoning TSSOP and QFP in favor of DFN, QFN, and LFCSP in recent years. For anything that does high-speed signaling or multiplexing above 1 Gbps (which is old by computer's standard) like USB 3.0, PCIe 1/2, QFN goes without the need for a mention (short of using BGA). But the thing is, even in simpler ICs like DC-DC controllers, you can see the same trend. Simple RFICs are another source of heavy users of these packages, reduced circuit parasitics is certainly a factor.
These packages are all leadless, and frequently with thermal pads at the bottom. An older term for leadless packages is BTC - Bottom Termination Components. [1] After a few successive and multiple failed QFN soldering attempts, I switched to ordering stencil, solder paste, and a hot plate. It worked perfectly on my first attempt, so I never looked back.
Unless you have top 10% soldering skills, which I don't (experienced smartphone repair technicians seems to have mastered the art of QFN), I found solder paste is required for maintaining your sanity with leadless packages. Furthermore, without reflow soldering, prototype assembly can be very time-consuming and takes hours, especially when you need 3 or more prototypes.
Occasionally, leadless packages also have optional difficulties turned on, completely eliminating the possibility of hand soldering, such as multiple bottom pads for different nets (to minimize parasitic inductance), or having two layers of contacts, one row on the exterior and on row on the interior.
> You can easily do small scale work with almost all SMT components without solder paste. [...] The one exception is BGA devices
And DFN, and QFN, and LFCSP, and...
Thanks to industrial and automotive users, some ICs still have QFP versions for these markets (due to their vibration resistance) that are friendly for hand operation, but you have to pay a premium.
Finally, even plain-old QFP chips have bottom thermal pad these days (in that case, you can manually apply a blob of solder on the PCB and reflow again with a hot air gun, but manually apply a drop of paste is easier to work with).
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[1] But these days it would make people think it's some kind of a Bitcoin mining ASIC. BTW, the last time I've checked, these ASICs are indeed QFN, so one can say they're BTC BTC chips...