I grew up when many electronics around me was lamp. Lamps will often go bad, they are easy to replace, but not very cheap to buy. Lamps are susceptible to mechanical vibrations. Lamps and devices containing them will get hot. The sound produced by lamp devices was OK, warm, but nothing special. And then recently I learned about other things. Lamps need high voltage, so the electrical safety is higher concern, PSUs are more complex as well. Lamp amps have high impedance output, unless you put an additional transformer after last stage. Lamps are not linear, so you either get a lot of harmonics, or if you use proper Class-A on a short linear piece of the diagram, you will get a highly inefficient amp.
Are there any good sounding competent lamp amps? Yes. This guy in below video got a very good DIY lamp speaker amp, which was a good match for his speakers (he has some vintage S30 from Russia).
His cat seems to agree.