Yes, steel, especially non heat treated 4130 crhomoly is repairable at just about any metal working shop. That's why it's the choice of bicycle tourers and custom frame builders. Also a steel frame is very dependable, bicycle enthusiasts usually rebuild thier steel frame a couple of times during its lifetime. Last year I bought a lugged steel road bike frame that has the same age as myself and build up with a mix of vintage and contemporary components with vintage looks.
Alloy, titanium and carbon fiber are lighter and that's what most consumers want, having watched Tour de France and bicycle industry marketing materials. Big brands facing increased competition from Asia started to put carbon frames of questionable quality on the market, so if you want an okay bike you are best served by alloy, because they're mass produced and the process is quite optimized and well understood. Titanium is basically unrepairable without special tooling and know how and it feels basically the same as alloy. It's stronger and more corrosion resistant.
The bike industry also puts a lot of new or proprietary standards on the market, especially when it comes to bottom backets. Other new standards include different fork spacing, head tube diameters, rear suspension couplers, proprietary frame integrated suspension and more recently integrated e-bike batteries. The worst offensers are Cannondale, Specialized, Trek and Cervelo.
If you want a bike with sensible standards you want a BSA threaded bottom bracket if it's a metal frame or BB86/92 press fit if it's a carbon frame, a fork with a 1 1/8" steerer or tappered from 1 1/8" to 1 1/2" steerer if it's a mountain bike or a high end road bike, a 34 mm or a 44 mm head tube, 135 mm O.L.D. rear and 100 mm front fork spacing for quick release skewers or 148 mm/110 mm boost spacing if it's a newer mountain bike or 142 mm/100 mm spacing if it's a newer road bike with thru axles, a seat post diameter of 27.2 if it's a road bike or 31.6 mm if it's a newer mountian bike. For brake mounts I prefer IS brake mounts because they're robust, don't have threads to cross thread and misalignment issues are not common, but modern road bikes come with the flat mount (FM) standard and newer alloy MTBs come with post mount (PM). What you probably don't want is a mountain bike with flat mount brakes, funny axle standards, direct derailleur mounts, integrated seat posts, integrated cockpits, full internal routing, lefty forks, integrated frame suspension and so on.