License production is probably one of the best way to get into engine manufacturing for an engine you know you will be using for decades to come. Once there is a Ws-13/19 engine at the right performance characteristics and if it is adopted for a JF-17 variant (and if the PAF procures the J-35 with the same engine) it would make sense to try to license produce the engine. Otherwise engine technology keeps advancing. We have to keep economies of scale into account. We also have a lot of other areas to focus on before aircraft engines. But I agree, automakers in Pakistan should have the ability to make the whole care including their own engines and transmissions.
I think it's important to preface that the goal of an in-house engine is literally that, to have an in-house engine. The point is to have a sanction-free solution that'll guarantee a bare minimum level of airpower no matter what. So, even an engine that's 20-30 years behind the current Western stuff is fine. It isn't ideal, but if it can get a contemporary fighter with modern-day radar, ECM, AAMs, PGBs, and SOWs in the air, then that's a workable start. However, there'll be a cost in maintenance issues, reliability issues, performance issues, etc, and that's where iterative, long-term development and improvement are critical. It's a multi-decade-long process, but IMO, getting a locally built engine (albeit not a very good one) can come sooner (10-15 years with healthy funding), and that alone is a significant step forward.
I say this because there's no point in 'waiting' for the WS-13 to reach an ideal level. We could have an opportunity to start developing an engine with Ukraine right now (their AI-9500F project), but we should accept that the engine will probably be dog food for a while. However, in the course of developing that engine, we would learn a lot more about gas turbines and build capacity that we can use to advance the fighter engine as well as develop simpler engines for cruise missiles, drones, etc. We could even branch the gas turbine tech into turboshafts for helicopters.
Will this hypothetical engine take at least 10-15 years to materialize? Sure, and that's probably the best-case scenario. Will it be behind everyone else's engine? Definitely, that's the cost of not starting this work back in the 1950s, 1960s, 1970s, 1980s, 1990s, 2000s, or even 2010s. However, will we manufacture our own engine and, potentially, build a fighter on a turnkey basis? That's the hope.
We should be frank about the JF-17's limitations, for example, but we can take pride in saying we have a credible air asset we can rely on no matter what. Is the JF-17 a relaxed stability, composite-heavy design? NOPE. Does it carry an AESA radar and lob a LRAAM at 100+ km at someone? YUP. Same idea here. Can this hypothetical engine take our JF-17 and NGFA up into the air? YUP. Can it, in theory, shoot down a Tejas with all the fancy bells and whistles (and heftier price-tag)? YUP.
@SQ8
With a long-term vision and sincere leadership, we can go from absolute zero today to a dogsh!t engine in 15 years...but go to a 'OK' engine in the next 15 years...and to a 'world-class' engine in the next 15 years. It'd be 45-50 years of development, but having that dogsh!t engine in the beginning would take us leaps and bounds over where we're at today. The rest is about institutional development, maturation and perfecting our labour, infrastructure, sciences, etc to get to the world-class design.
tldr; I'd take a dogsh!t engine today if it meant we can build it in Pakistan 100%. I have full confidence in my people that with the right vision and leadership, we could take it to the world-class level within 50 years, probably sooner if we up our ambition and our relentlessness.