The modern amp covers 160, though, along with the other bands, so of one is
lazy (hence his name), the linear is a reasonable approach.
Colin K7FM

This is what I suspected when I first asked my question, but many
posters here inferred it was not a reasonable approach.
Lazy Senior

I use low-level modulation and a linear amplifier to work AM. My
advice in selecting a linear amplifier for that mode is to focus on
the heat dissipation capability of the final devices, be they tubes
or transistors. Although the theoretical efficiency of a class-B
amplifier is something like 67%, that applies to a signal swinging
the amplifier between cutoff and saturation. For the carrier-wave
level, which will be 1/4 the peak output power, the operating point
will be in the regions of the characteristic curves that are much
less efficient. I typically get 25-30% from my SB-220 with a
250-watt carrier output power. Worst-casing a desired 375-watt
carrier level with 25% efficiency gives a final-power-dissipation
requirement of 1125 watts - a stretch for a pair of 3-500's, somewhat
easier with a 3CX1200 and easier still with an 8877/3CX1500.
The steady-state power-supply requirements are also pretty strenuous -
1500 watts - although most recent designs (Ameritron AL-1500) are
capable of this.

The efficiency argument against using a linear and in favor of
high-level modulation is seen to be fairly strong. However there
are a few additional factors to consider: As noted by another
poster, the modulator has to be powered up and has its own efficiency
issues. Also, using a linear amplifier rather than a Class-C final
reduces the harmonic-attenuation problem considerably (as well as
neighborhood TVI complaints). Modulation done at low levels is
more "controllable" with modestly sized components for splatter
filters, negative-peak loading/clipping and negative feedback. I
use an SSB transceiver (a Kenwood TS-850) for the extreme form
of this "modulation control", since my transmit signal is passed
through the same 6 kHz IF filter used for reception - effectively
filtering out splatter and out-of-channel IMD. The last advantage
of linear amplifier use, stated in the beginning of this thread, is,
of course, the ready availability of commercial units, both new and
used. For a dual-mode station (AM and SSB), the investment in
the amplifier pays a double dividend while, at the same time,
breathing new life into (and a whopping signal out of) many cherished
vintage low-power AM transmitters.

Jim, K7JEB